Epoxy resin adhesive material for cable as well as preparation method, application and recovery method of epoxy resin adhesive material

Abstract

The invention discloses an epoxy resin adhesive material for cables as well as a preparation method, application and a recovery method thereof, and relates to the field of adhesive materials for cables. The epoxy resin adhesive material for the cable is prepared from the following components in parts by mass: 0.001 to 0.5 part of catalyst, 5 to 20 parts of epoxy resin, 1 to 30 parts of thiol compound and 1 to 20 parts of isocyanate compound. The epoxy resin adhesive material for the cable has excellent mechanical strength, dielectric property and self-repairing performance, not only can meet the application requirements of the high-voltage cable under complex working conditions, but also can promote efficient utilization and cyclic regeneration of resources.

Description

Technical Field

[0001] The present invention relates to the field of adhesive materials for cables, and in particular to an epoxy resin adhesive material for cables, a preparation method thereof, an application thereof, and a recycling method thereof. Background Art

[0002] Cables are a vital component of a safe and stable power supply system for urban power grids. During use, due to changes in ambient temperature and the cable's own heating, the insulation and outer sheath of the cables can age and become brittle, reducing the cable's service life. Therefore, developing a cable resin adhesive with high mechanical and dielectric properties and strong self-healing properties is a research priority in this field.

[0003] At present, commonly used cable insulation materials are plastic materials such as polyethylene and cross-linked polyethylene. These plastic materials have poor mechanical properties and are easily damaged when subjected to external force impact, thus affecting the performance of the cable. At this stage, most of them use silicone resins, phenolic resins, urea-formaldehyde resins, epoxy resins, etc. to improve the mechanical strength of cable resin glue, but these materials have limited improvement on mechanical strength, and these materials cannot achieve self-repair and reuse, resulting in high cable maintenance costs, environmental pollution and waste of resources.

[0004] Therefore, how to provide a resin glue for cables that has excellent mechanical strength, dielectric properties and can achieve self-repair, thereby improving the performance of the cables, is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0005] The main purpose of the present invention is to provide an epoxy resin adhesive material for cables, a preparation method, an application and a recycling method thereof, so as to solve the problem in the prior art that resin adhesives for cables are difficult to have both excellent mechanical strength and dielectric properties and are difficult to achieve self-repair and reuse.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an epoxy resin adhesive material for cables, which comprises the following components in parts by mass: 0.001 to 0.5 parts by mass of a catalyst, 5 to 20 parts by mass of an epoxy resin, 1 to 30 parts by mass of a thiol compound, and 1 to 20 parts by mass of an isocyanate compound.

[0007] Further, the thiol compound includes dihydric thiol and / or polythiol; preferably, the dihydric thiol includes at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 2,6-dimercaptopurine, 1,4-benzenedithiol, 1,4-dimethylbenzenedithiol, 3,6-dioxa-1,8-octanedithiol, 3,4-disulfatotoluene, and 4,4'-thiobisthiophenol; preferably, the polythiol includes at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate).

[0008] Furthermore, the isocyanate compound includes diisocyanate and / or polyisocyanate;

[0009] Preferably, the diisocyanate comprises at least one of m-xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, p-phenylene diisocyanate, and 1,3-phenylene diisocyanate;

[0010] Preferably, the polyisocyanate includes at least one of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and dicyclohexylmethane-4,4-diisocyanate trimer.

[0011] Furthermore, the epoxy resin includes at least one of bisphenol A epoxy resin and hydrogenated bisphenol A epoxy resin.

[0012] Furthermore, the catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, 1-methyl-1H-imidazole, N-ethylmorpholine, N,N-dimethylbenzylamine, and N,N'-diethylpiperazine.

[0013] Furthermore, the epoxy resin adhesive material for cables comprises the following components, calculated in parts by mass: 0.02 to 0.1 parts by mass of a catalyst, 10 parts by mass of an epoxy resin, 5 to 15 parts by mass of a thiol compound, and 3 to 10 parts by mass of an isocyanate compound;

[0014] Among them, the thiol compound includes at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), 4,4'-thiobisthiophenol, and 1,6-hexanedithiol; the isocyanate compound includes 1,3-bis(1-isocyanato-1-methylethyl)benzene, hexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane-4,4-diisocyanate; the catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, and 1-methyl-1H-imidazole.

[0015] A second aspect of the present invention provides a method for preparing the epoxy resin adhesive material for cables according to the first aspect, comprising the following steps:

[0016] S1, mixing a catalyst, an epoxy resin, a thiol, and an isocyanate according to parts by mass, and stirring to obtain an epoxy resin sizing material;

[0017] S2, pouring the epoxy resin into a mold to obtain a sample to be cured;

[0018] S3, after the sample to be cured is cured, the epoxy resin adhesive material for the cable is obtained.

[0019] Furthermore, the temperature of the curing treatment is 80° C. to 140° C., and the time of the curing treatment is 2 hours to 8 hours.

[0020] The third aspect of the present invention provides a cable, comprising a conductive core, an outer covering layer wrapped around the conductive core, and a filling layer filled between the conductive core and the outer covering layer, wherein the filling layer comprises the epoxy resin adhesive material for cable according to the first aspect, or the epoxy resin adhesive material for cable obtained by the preparation method of the second aspect.

[0021] A fourth aspect of the present invention provides a method for recycling epoxy resin adhesive material for cables, which is used to recycle the epoxy resin adhesive material for cables, comprising the following steps:

[0022] The cables to be recycled are crushed with epoxy resin adhesive material to obtain epoxy resin powder;

[0023] Hot pressing the epoxy resin powder to obtain the epoxy resin adhesive material for the repaired cable;

[0024] The temperature of the hot pressing molding is 100° C. to 150° C., the pressure of the hot pressing molding is 3 MPa to 10 MPa, and the time of the hot pressing molding is 1 hour to 2 hours.

[0025] The technical solution of the present invention is applied. By limiting the components and proportions of epoxy resin glue, under the action of a catalyst, isocyanate compounds react with thiol compounds to form dynamic thiocarbamate bonds. The presence of such chemical bonds helps to improve the dielectric strength and dielectric constant of epoxy resin glue, thereby improving the dielectric properties of epoxy resin glue. This ensures that epoxy resin glue can maintain good electrical stability under high voltage conditions, avoids the generation of dielectric loss and leakage current, and enhances the operational safety of the cable. At the same time, such chemical bonds can dissociate and reorganize at higher temperatures, allowing epoxy resin glue to change its topological network structure to a certain extent, thereby achieving self-repair and reuse of epoxy resin glue. Even if epoxy resin glue has been cured, it can still be reused by heating and reshaping, greatly reducing the consumption of epoxy resin glue and the impact on the environment. In addition, a strong covalent bond is formed between epoxy resin and thiol compounds, significantly improving the mechanical strength of epoxy resin glue, and the introduction of thiol compounds helps to form a denser cross-linked network, thereby enhancing the toughness and impact resistance of epoxy resin glue. The epoxy resin adhesive material for the cable can not only meet the application requirements of high-voltage cables under complex working conditions, but also promote the efficient utilization and recycling of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a method for testing the lap shear strength of an epoxy resin adhesive material according to one embodiment of the present invention;

[0027] Figure 2 1 is a displacement relationship diagram of the lap shear strength of the epoxy resin adhesive material in Example 1 of the present invention;

[0028] Figure 3 is a stress-strain curve diagram of the epoxy resin adhesive material in Example 1;

[0029] Figure 4 This is the Weibull distribution diagram of the breakdown AC field strength of the epoxy resin adhesive material in Example 1. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0031] As described in the background of the present invention, the existing resin adhesives for cables have difficulty in achieving both excellent mechanical strength and dielectric properties, as well as difficulty in achieving self-repair and reuse. To address the above problems, in a typical embodiment of the present invention, an epoxy resin adhesive material for cables is provided. The epoxy resin adhesive material for cables comprises the following components, measured in parts by mass: 0.001 to 0.5 parts by mass of a catalyst, 5 to 20 parts by mass of an epoxy resin, 1 to 30 parts by mass of a thiol compound, and 1 to 20 parts by mass of an isocyanate compound.

[0032] Isocyanate compounds react with thiol compounds to form thiol carbamate bonds. The presence of these chemical bonds helps increase the dielectric strength and dielectric constant of epoxy resin adhesives, thereby improving the dielectric properties of epoxy resin adhesives. This ensures that the epoxy resin adhesive can maintain good electrical stability under high voltage conditions, avoids dielectric loss and leakage current, and enhances the operational safety of the cable.

[0033] Once cured, traditional epoxy resin adhesives are difficult to reprocess and reuse, resulting in a large amount of material waste and potential environmental problems. The present invention, by adding a catalyst to the formula, can promote the formation of dynamic thiocarbamate bonds. This type of bond can dissociate and reorganize at higher temperatures. By introducing dynamic covalent bonds in the cross-linked network, the epoxy resin adhesive is allowed to change its topological network structure to a certain extent, and promote stress relaxation and reversible decrosslinking through bond exchange, so that the epoxy resin has reprocessing and self-repairing properties, realizing the self-repair and reuse of the epoxy resin adhesive. This means that even if the material has been cured, it can still be reused by heating and reshaping, greatly reducing material consumption and environmental impact.

[0034] The strong covalent bond between epoxy resin and thiol compounds significantly improves the mechanical strength of epoxy resin adhesive. The introduction of thiol compounds helps to form a denser cross-linking network, thereby enhancing the toughness and impact resistance of epoxy resin adhesive, which is crucial for withstanding the high mechanical stress generated during the operation of high-voltage cables.

[0035] Therefore, the epoxy resin adhesive material for cables provided by the present invention, under the combined action of chemical reactions between components and the chemical bonds formed, helps to improve the mechanical strength and dielectric properties of the epoxy resin adhesive, while realizing the self-repair and reuse of the epoxy resin adhesive, which can not only meet the application requirements of high-voltage cables under complex working conditions, but also promote the efficient utilization and recycling of resources.

[0036] Thiol compounds directly affect the crosslinking density, mechanical strength, and dielectric properties of epoxy resin adhesive materials for cables, and also affect their self-repair and reusability. In order to further optimize the performance of epoxy resin adhesive materials for cables. In some embodiments, thiol compounds include dihydric thiols and / or polythiols. Among them, dihydric thiols can provide two active groups to participate in the crosslinking reaction, which can effectively promote the formation of a high-density three-dimensional crosslinked network, forming a more ordered and stable network structure, and help further improve the mechanical strength and dielectric properties of epoxy resin adhesive materials for cables. For example, dithiols can include at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 2,6-dimercaptopurine, 1,4-benzenedithiol, 1,4-dimethylbenzenedithiol, 3,6-dioxa-1,8-octanedithiol, 3,4-disulfatotoluene, and 4,4'-thiobisthiophenol. Polythiols can provide multiple active thiol (-SH) groups to participate in the reaction, which not only accelerates the crosslinking process but also enables the construction of more complex crosslinked structures, thereby improving the toughness, adhesion, and self-healing ability of epoxy resin adhesives for cables. The presence of polythiols allows epoxy resin adhesives for cables to restore their original network structure and performance after damage through bond exchange reactions between thiol compounds and isocyanate compounds. For example, the polythiol may include at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate).

[0037] By using this specific combination of thiol compounds, the present invention allows for precise control of the chemical reactions of epoxy resin adhesives to achieve the desired high performance. Furthermore, the selection of polythiols and multiple dithiols provides flexibility in adjusting the physical and chemical properties of epoxy resin adhesives, allowing the most appropriate formulation to be selected based on different application requirements.

[0038] In some embodiments, the isocyanate compound includes a diisocyanate and / or a polyisocyanate. Among them, the diisocyanate includes but is not limited to at least one of m-phenylenediisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, p-phenylenediisocyanate, and 1,3-phenylenediisocyanate. These diisocyanates can undergo a click reaction with thiol compounds to generate thiocarbamate bonds, which form a stable cross-linked network in the epoxy resin adhesive, thereby greatly improving the mechanical strength and stress resistance of the adhesive. Especially in the environment of cable insulation repair, the epoxy resin adhesive needs to withstand high pressure and various mechanical stresses. The selection of the above-mentioned diisocyanates can significantly enhance the stability and durability of the epoxy resin adhesive under such conditions. Polyisocyanates include, but are not limited to, at least one of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and dicyclohexylmethane-4,4-diisocyanate trimer. These polyisocyanates provide more reactive sites, forming a more complex, multidimensional cross-linked structure. This highly cross-linked network not only improves the rigidity and dimensional stability of the epoxy adhesive, but also further enhances its dielectric properties, making it more suitable for repairing epoxy damage to cable terminations. Furthermore, the presence of the polyisocyanate enhances the epoxy adhesive's self-healing ability after damage, ensuring that the adhesive maintains its essential properties even after damage.

[0039] By flexibly selecting these two types of isocyanate compounds, the present invention allows for precise control of epoxy resin adhesive performance indicators to meet the specific requirements of different application scenarios. For example, by selecting the appropriate isocyanate compound type and ratio, the material's hardness, flexibility, and self-healing efficiency can be balanced, ensuring reliable bonding and insulation protection in the complex environment of high-voltage cable terminals while also rapidly recovering from damage, thereby extending the cable's service life and reducing maintenance costs.

[0040] In order to further optimize the bonding performance, mechanical strength, dielectric properties and functionality of epoxy resin adhesive materials for cables. In some embodiments, the epoxy resin includes at least one of bisphenol A epoxy resin and hydrogenated bisphenol A epoxy resin. Among them, bisphenol A epoxy resin has excellent thermal stability and high mechanical strength. Using bisphenol A epoxy resin in the formulation of epoxy resin adhesive materials for cables can ensure that the epoxy resin adhesive has sufficient bonding ability and long-term stability in complex environments such as cable terminals. It can also provide good dielectric properties to ensure the safe operation of the power system. Compared with unhydrogenated bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin has a lower dielectric constant and dielectric loss, as well as higher insulation resistance and dielectric strength. This makes hydrogenated bisphenol A epoxy resin suitable for high-frequency or high-voltage power applications, can significantly reduce signal attenuation and energy loss, while improving the arc resistance and corona resistance of the epoxy resin adhesive, which contributes to efficient insulation repair of cable terminals.

[0041] Catalysts can significantly affect the reaction rate and the performance of the final product. To further improve the overall performance of epoxy resin adhesives, in some embodiments, the catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, N-ethylmorpholine, N,N-dimethylbenzylamine, and N,N'-diethylpiperazine. For example, triethylamine, as a proton acceptor, can effectively catalyze the reaction between epoxy resin and thiol compounds or isocyanate compounds, promoting the formation of thiourethane bonds, helping to improve the efficiency and yield of the reaction, ensuring that the epoxy resin adhesive cures quickly and forms a stable cross-linked network. N,N-diisopropylethylamine maintains good catalytic activity at low temperatures and is suitable for use under conditions requiring control of curing temperature and speed. Similar to triethylamine, N,N-diisopropylethylamine can accelerate the reaction of thiol compounds and isocyanate compounds with epoxy resins. At the same time, its specific chemical structure may also affect the formation of the cross-linked network, thereby helping to further improve the mechanical and dielectric properties of the epoxy resin adhesive. 1-Methyl-1H-imidazole has high catalytic activity and selectivity, and can promote the reaction between epoxy resin and thiol compounds to form a high-density cross-linked network, which helps to improve the mechanical strength and dielectric properties of epoxy resin adhesives. At the same time, 1-methyl-1H-imidazole remains active at high temperatures, allowing epoxy resin adhesives to cure over a wide temperature range. Pyridine, as an alkaline catalyst, can accelerate the reaction between epoxy resin and thiol compounds or isocyanate compounds, promote the formation of thiocarbamate bonds, help optimize curing conditions, reduce energy consumption, and help form a more uniform and dense cross-linked network, thereby improving the overall performance of epoxy resin adhesives.

[0042] In order to further improve the comprehensive performance of epoxy resin adhesive. In some embodiments, the epoxy resin adhesive material for cable includes the following components: 0.02-0.1 parts by mass of catalyst, 10 parts by mass of epoxy resin, 5-15 parts by mass of thiol compound, and 3-10 parts by mass of isocyanate compound; wherein the thiol compound includes at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), 4,4'-thiobisthiophenol, and 1,6-hexanedithiol; the isocyanate compound includes 1,3-bis(1-isocyanato-1-methylethyl)benzene, hexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane-4,4-diisocyanate; the catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, and 1-methyl-1H-imidazole. By further controlling the ratio and specific types of each component, the best performance can be achieved.

[0043] A second aspect of the present invention provides a method for preparing the epoxy resin adhesive material for cables according to the first aspect, comprising the following steps:

[0044] S1, mixing a catalyst, an epoxy resin, a thiol compound, and an isocyanate compound according to parts by mass, and stirring to obtain an epoxy resin sizing material;

[0045] S2, pouring the epoxy resin into the mold to obtain a sample to be cured;

[0046] S3, after the sample to be cured is cured, an epoxy resin adhesive material for cables is obtained.

[0047] Specifically, in step S1, according to required molar ratio, catalyst, epoxy resin, thiol compound and isocyanate compound are accurately weighed. These raw materials are rapidly stirred in appropriate containers, with the purpose of ensuring that each component is fully mixed to form uniform epoxy resin sizing agent. In step S2, epoxy resin sizing agent is poured into a pre-prepared mold, and the shape and thickness of the final product are controlled by the shape and size of the mold. In step S3, the sample to be cured formed in step S2 is placed under specific curing conditions to promote the formation of a cross-linked network, thereby improving the mechanical strength, dielectric properties and self-repairing ability of the epoxy resin glue.

[0048] The present invention, through the above-mentioned preparation method, can efficiently produce an epoxy resin adhesive with high mechanical strength, high dielectric properties, and self-repairing capabilities. It is suitable for the field of cable insulation, especially for the rapid repair of epoxy damage on cable terminals. This preparation method is not only suitable for laboratory research and development, but also easy to implement in industrial production, meeting the specific needs of different power equipment and application environments.

[0049] In some embodiments, the curing temperature is 80°C to 140°C, for example, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or a range consisting of any two thereof. Higher temperatures can accelerate the cross-linking reaction, but may cause side reactions or decomposition, affecting the performance of the epoxy resin adhesive. Lower temperatures can avoid these problems, but the curing process may become slower. Therefore, by controlling the curing temperature to 80°C to 140°C, it helps to achieve rapid and effective curing while ensuring the performance of the epoxy resin adhesive.

[0050] In some embodiments, the curing time is 2 hours to 8 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or a range consisting of any two of them. The length of the curing time affects the crosslinking density and physical property maturity of the epoxy resin glue. A longer curing time can ensure that the crosslinking reaction is thoroughly completed and a tighter network structure is formed, but it will increase production time and energy consumption. On the contrary, a shorter curing time can improve production efficiency, but a higher temperature or a stronger catalyst may be required to ensure the complete reaction. By controlling the curing time to 2 hours to 8 hours, while ensuring product quality, it helps to improve production efficiency.

[0051] The third aspect of the present invention provides a cable, comprising a conductive core, an outer covering layer wrapped around the conductive core, and a filling layer filled between the conductive core and the outer covering layer, the filling layer comprising the epoxy resin adhesive material for cable provided by the first aspect, or the epoxy resin adhesive material for cable obtained by the preparation method provided by the second aspect.

[0052] The basic structure of the cable includes a conductive core, an outer layer and a filling layer located between the two. Since the filling layer includes the above-mentioned high-performance epoxy resin adhesive material for cables, it helps to provide electrical insulation properties and has sufficient mechanical strength to resist external forces such as stretching, twisting and compression during the installation and operation of the cable, thereby extending the service life of the cable; at the same time, the self-healing performance of the epoxy resin adhesive means that when the cable is slightly damaged, the filling layer can automatically repair and restore its original performance without the need for immediate human intervention, which significantly improves the durability and maintenance convenience of the cable; since the epoxy resin adhesive is recyclable, even if the cable is scrapped, the material of the filling layer can be recycled and reused, reducing the environmental burden and complying with the concept of circular economy and sustainable development.

[0053] Specifically, the conductive core is the core component of the cable, and the conductive core is responsible for transmitting current or signals. The outer layer of the outer material provides additional mechanical protection and environmental protection to prevent external factors such as moisture, chemicals and ultraviolet radiation from damaging the internal components. The filling layer effectively isolates the conductive core from the outer layer of the outer material, maintaining the electrical performance and safety of the cable. By using the epoxy resin adhesive of the present invention, the filling layer not only enhances the electrical and mechanical properties of the cable, but also gives it the ability to self-repair and reprocess. The cable is particularly suitable for application requirements in high voltage and harsh environments, such as deep-sea cables, underground cables, industrial cables and aerospace cables.

[0054] A fourth aspect of the present invention provides a method for recycling epoxy resin adhesive material for cables, which is used to recycle the epoxy resin adhesive material for cables, comprising the following steps:

[0055] The cables to be recycled are crushed with epoxy resin adhesive material to obtain epoxy resin powder;

[0056] Hot pressing the epoxy resin powder to obtain the epoxy resin adhesive material for the repaired cable;

[0057] The temperature of the hot pressing molding is 100-150° C., the pressure of the hot pressing molding is 3-10 MPa, and the time of the hot pressing molding is 1-2 hours.

[0058] Specifically, the epoxy resin adhesive material used in the cable recycling process is pulverized. This process is typically performed at room temperature, using a grinder or crushing device to break the cured epoxy resin adhesive into a fine powder. The purpose of pulverization is to increase the surface area of ​​the epoxy resin adhesive, allowing for more efficient reorganization and resolidification during the subsequent hot pressing process. Next, the pulverized epoxy resin powder is subjected to hot pressing under specific conditions of temperature, pressure, and time. Specifically, the hot pressing temperature is 100-150°C, the pressure is 3-10 MPa, and the time is 1-2 hours. These parameters are selected based on the dissociation and recombination capabilities of the dynamic covalent bonds (such as thiocarbamate bonds) in the epoxy resin adhesive. During the hot pressing process, the high temperature and pressure promote the rearrangement and recombination of the dynamic bonds in the powder, forming a new cross-linked network, thereby restoring the mechanical and dielectric properties of the epoxy resin adhesive, as well as its self-healing ability. This process not only regenerates the epoxy resin adhesive but also ensures that the properties of the repaired epoxy resin adhesive approach or reach those of the virgin material.

[0059] The present invention helps avoid excessive cross-linking or decomposition of the epoxy resin adhesive by controlling the conditions of the hot pressing process. Excessive temperatures may cause the epoxy resin adhesive to decompose. By optimizing the pressure and time, the efficiency of the repair process and the high quality of the epoxy resin adhesive after repair are ensured.

[0060] The recycling method of the present invention significantly reduces the environmental impact of waste epoxy resin adhesive, while also conserving resources, reducing production costs, and promoting the sustainable use of epoxy resin adhesive. It is particularly useful for treating old or damaged cable terminal epoxy resin adhesive. Notably, the implementation of the recycling method of the present invention relies on the aforementioned high-performance epoxy resin adhesive, namely, the epoxy resin adhesive contains dynamic bonds that can dissociate and recombine at higher temperatures to ensure the feasibility of the repair process.

[0061] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0062] Example 1

[0063] 1. The epoxy resin adhesive material for the cable in this embodiment includes 0.03g of triethylamine, 10g of E51 bisphenol A epoxy resin, 13.6g of trimethylolpropane tris(3-mercaptopropionate) and 6.24g of 1,3-bis(1-isocyanato-1-methylethyl)benzene.

[0064] 2. The preparation method of the epoxy resin adhesive material for cables in this embodiment includes the following steps:

[0065] S1, 0.03 g of triethylamine, 10 g of E51 bisphenol A epoxy resin, 13.6 g of trimethylolpropane tris(3-mercaptopropionate), and 6.24 g of 1,3-bis(1-isocyanato-1-methylethyl)benzene were added to a flask in sequence, and the mixture was stirred magnetically at room temperature to obtain an epoxy resin compound;

[0066] S2, degassing the epoxy resin material by vacuum and stirring for 10 minutes, and then pouring it into the mold to obtain a sample to be cured;

[0067] S3, curing the sample to be cured at 100° C. for 6 hours to obtain a cable epoxy resin adhesive material.

[0068] Example 2

[0069] 1. The epoxy resin adhesive material for cables in this embodiment includes 0.026 g of N,N-diisopropylethylamine, 10 g of hydrogenated E51 bisphenol A epoxy resin, 12.46 g of pentaerythritol tetrakis(3-mercaptopropionate) and 4.28 g of hexamethylene diisocyanate.

[0070] 2. The preparation method of the epoxy resin adhesive material for cables in this embodiment includes the following steps:

[0071] S1, 0.026 g of N,N-diisopropylethylamine, 10 g of hydrogenated E51 bisphenol A epoxy resin, 12.46 g of pentaerythritol tetrakis(3-mercaptopropionate), and 4.28 g of hexamethylene diisocyanate were added to a flask in sequence, and the mixture was stirred evenly with a magnetic stirrer at room temperature to obtain an epoxy resin sizing material;

[0072] S2, degassing the epoxy resin material by vacuum and stirring for 15 minutes, and then pouring it into the mold to obtain a sample to be cured;

[0073] S3, curing the sample to be cured at 120° C. for 4 hours to obtain a cable epoxy resin adhesive material.

[0074] Example 3

[0075] 1. The epoxy resin adhesive material for cables in this embodiment includes 0.05 g of 1-methyl-1H-imidazole, 10 g of E51 bisphenol A epoxy resin, 12.8 g of 4,4'-thiobisthiophenol and 5.63 g of isophorone diisocyanate.

[0076] 2. The preparation method of the epoxy resin adhesive material for cables in this embodiment includes the following steps:

[0077] S1, adding 0.05 g of 1-methyl-1H-imidazole, 10 g of E51 bisphenol A epoxy resin, 12.8 g of 4,4'-thiobisthiophenol, and 5.63 g of isophorone diisocyanate to a flask in sequence, and stirring the mixture magnetically at room temperature to obtain an epoxy resin compound;

[0078] S2, degassing the epoxy resin material by vacuum and stirring for 15 minutes, and then pouring it into the mold to obtain a sample to be cured;

[0079] S3, curing the sample to be cured at 100° C. for 6 hours to obtain a cable epoxy resin adhesive material.

[0080] Example 4

[0081] 1. The epoxy resin adhesive material for cables in this embodiment includes 0.10 g of triethylamine, 10 g of E51 bisphenol A epoxy resin, 7.66 g of 1,6-hexanedithiol and 6.68 g of dicyclohexylmethane-4,4-diisocyanate.

[0082] 2. The preparation method of the epoxy resin adhesive material for cables in this embodiment includes the following steps:

[0083] S1, adding 0.10 g of triethylamine, 10 g of E51 bisphenol A epoxy resin, 7.66 g of 1,6-hexanedithiol, and 6.68 g of dicyclohexylmethane-4,4-diisocyanate into a flask in sequence, and stirring the mixture magnetically at room temperature to obtain an epoxy resin compound;

[0084] S2, degassing the epoxy resin material by vacuum and stirring for 15 minutes, and then pouring it into the mold to obtain a sample to be cured;

[0085] S3, curing the sample to be cured at 140° C. for 6 hours to obtain a cable epoxy resin adhesive material.

[0086] Comparative Example 1

[0087] 1. The epoxy resin adhesive material for cables in this embodiment includes hydrogenated E51 bisphenol A epoxy resin, curing agent MTHPA and accelerator DMP-30 (mass ratio is 100:80:1).

[0088] 2. The preparation method of the epoxy resin adhesive material for cables in this embodiment includes the following steps:

[0089] S1, first accurately weigh epoxy resin E51, curing agent MTHPA and accelerator DMP-30 in a flask (mass ratio of 100:80:1), and magnetically stir at room temperature for 15 minutes to obtain a mixed epoxy resin material;

[0090] S2, degassing the mixed epoxy resin material by vacuum and stirring for 15 minutes, and then pouring it into a mold to obtain a sample to be cured;

[0091] S3, keeping the sample to be cured at 80° C. for 2 h, 105° C. for 2 h, and 120° C. for 4 h to obtain a cable epoxy resin adhesive material.

[0092] Test example

[0093] 1. Lap shear strength test

[0094] The lap shear strength test is mainly used to determine the bonding strength of epoxy resin adhesive when subjected to shear force. Figure 1 As shown, two identical specimens (such as metal plates) are selected, the surfaces are cleaned to remove grease and dirt, and epoxy resin adhesive is directly applied between the two overlapping specimens. The length of the overlapping area is 2.5 cm, the width is 1 cm, and the thickness is 0.1 mm. After curing at 80-140°C for 2h-4h, an epoxy resin adhesive layer is formed; the shear tester is started, and a shear force is applied to the specimen at a certain rate until the epoxy resin adhesive layer is destroyed, and the maximum load at this time is recorded; the lap shear strength is calculated using the maximum load value, the width and length of the specimen lap area, and the calculation formula is lap shear strength = maximum load / surface area of ​​the specimen lap area.

[0095] 2. Stress-strain curve

[0096] Clamp the two ends of the epoxy resin adhesive material in the upper and lower fixtures of a material testing machine (such as a universal testing machine). Start the testing machine and stretch the epoxy resin adhesive material at a constant speed (such as 5mm / min) until the epoxy resin adhesive material breaks. During the stretching process, the testing machine will continuously record the applied force (load) and the change in specimen length. The load data is used to calculate stress, and the length change data is used to calculate strain; using the collected data, a stress-strain curve is plotted in the coordinate system. The horizontal axis represents strain (Strain) and the vertical axis represents stress (Stress).

[0097] 3. Weibull distribution of AC field strength

[0098] Using high-voltage testing equipment, a gradually increasing AC voltage was applied to the epoxy resin adhesive material until breakdown occurred, and the corresponding breakdown voltage was recorded. The breakdown voltage data of all samples were collected and fitted using the Weibull distribution model to calculate the average breakdown field strength (Eb) and shape parameter (β).

[0099] 4. Recycling methods of epoxy resin adhesive materials

[0100] The epoxy resin adhesive material is repaired as follows: the epoxy resin adhesive material is placed in a grinder and crushed into powder, then an appropriate amount of sample is placed in a square hot pressing mold, and the thickness of the prepared sample is ensured to be about 0.2 mm. It is hot pressed at a temperature of 150°C and a pressure of 10 MPa for 1 hour to 2 hours to obtain the recycled epoxy resin adhesive material.

[0101] The test results are shown in Table 1.

[0102] Table 1

[0103]

[0104] The lap shear strength of the epoxy resin adhesive material in Example 1 is shown in FIG. Figure 2 The measured lap shear strength is 12MPa, proving that the epoxy resin adhesive material has excellent bonding properties.

[0105] The stress-strain curve of the epoxy resin adhesive material in Example 1 is shown in FIG. Figure 3 The measured tensile modulus was 1.26±0.14 GPa, the breaking strength was 54.34±5.03, and the breaking elongation was 7.91±2.35%, proving that the epoxy resin adhesive material has excellent mechanical properties.

[0106] The Weibull distribution of the breakdown voltage of the epoxy resin adhesive material in Example 1 is shown in FIG. Figure 4 .according to Figure 4 It can be seen that the AC breakdown field strength E of the epoxy resin adhesive material in Example 1 is bThe β value is 75.4 kV / mm, and the shape parameter β is 26.69. The high β value indicates that the epoxy resin adhesive material has good uniformity, indicating that the epoxy resin adhesive material has excellent dielectric properties.

[0107] As can be seen from Table 1, the epoxy resin adhesive material for cables provided by the present invention has excellent mechanical strength, dielectric properties and bonding properties, and can also achieve self-repair and reuse, which helps to increase the service life of the cable.

[0108] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An epoxy resin adhesive material for cables, characterized in that: The epoxy resin adhesive material for cables includes the following components in parts by mass: 0.001 to 0.5 parts by mass of a catalyst, 5 to 20 parts by mass of an epoxy resin, 1 to 30 parts by mass of a thiol compound, and 1 to 20 parts by mass of an isocyanate compound.

2. The epoxy resin adhesive material for cables according to claim 1, characterized in that: The thiol compound includes dihydric thiol and / or polyhydric thiol; Preferably, the dihydric thiol includes at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 2,6-dimercaptopurine, 1,4-benzenedithiol, 1,4-dimethylbenzenedithiol, 3,6-dioxa-1,8-octanedithiol, 3,4-disulfatotoluene, and 4,4'-thiobisthiophenol; Preferably, the polythiol includes at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate).

3. The epoxy resin adhesive material for cable according to claim 1, characterized in that: The isocyanate compound includes diisocyanate and / or polyisocyanate; Preferably, the diisocyanate comprises at least one of m-xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, p-phenylene diisocyanate, and 1,3-phenylene diisocyanate; Preferably, the polyisocyanate includes at least one of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and dicyclohexylmethane-4,4-diisocyanate trimer.

4. The epoxy resin adhesive material for cables according to claim 1, characterized in that: The epoxy resin includes at least one of bisphenol A epoxy resin and hydrogenated bisphenol A epoxy resin.

5. The epoxy resin adhesive material for cable according to claim 1, characterized in that: The catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, 1-methyl-1H-imidazole, N-ethylmorpholine, N,N-dimethylbenzylamine, and N,N'-diethylpiperazine.

6. The epoxy resin adhesive material for cables according to any one of claims 1 to 5, characterized in that: The epoxy resin adhesive material for cables comprises the following components in parts by mass: 0.02 to 0.1 parts by mass of the catalyst, 10 parts by mass of the epoxy resin, 5 to 15 parts by mass of the thiol compound, and 3 to 10 parts by mass of the isocyanate compound; Among them, the thiol compound includes at least one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), 4,4'-thiobisthiophenol, and 1,6-hexanedithiol; the isocyanate compound includes 1,3-bis(1-isocyanato-1-methylethyl)benzene, hexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane-4,4-diisocyanate; and the catalyst includes at least one of triethylamine, N,N-diisopropylethylamine, 1-methyl-1H-imidazole, pyridine, and 1-methyl-1H-imidazole.

7. A method for preparing the epoxy resin adhesive material for cables according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, mixing a catalyst, an epoxy resin, a thiol, and an isocyanate according to parts by mass, and stirring to obtain an epoxy resin sizing material; S2, pouring the epoxy resin into a mold to obtain a sample to be cured; S3, after the sample to be cured is cured, the epoxy resin adhesive material for the cable is obtained.

8. The method for preparing epoxy resin adhesive material for cable according to claim 7, characterized in that: The temperature of the curing treatment is 80° C. to 140° C., and the time of the curing treatment is 2 hours to 8 hours.

9. A cable, characterized in that: It comprises a conductive core, an outer packaging material layer wrapped around the conductive core, and a filling layer filled between the conductive core and the outer packaging material layer, wherein the filling layer comprises the epoxy resin adhesive material for cable according to any one of claims 1 to 6, or the epoxy resin adhesive material for cable obtained by the preparation method of the epoxy resin adhesive material for cable according to claim 7 or 8.

10. A method for recycling epoxy resin adhesive material for cables, characterized in that: The method for recycling the epoxy resin adhesive material for cables according to any one of claims 1 to 6, or the epoxy resin adhesive material for cables obtained by the preparation method of the epoxy resin adhesive material for cables according to claim 7 or 8, comprises the following steps: The cables to be recycled are crushed with epoxy resin adhesive material to obtain epoxy resin powder; Hot-pressing the epoxy resin powder to obtain a repaired cable epoxy resin adhesive material; The temperature of the hot pressing molding is 100° C. to 150° C., the pressure of the hot pressing molding is 3 MPa to 10 MPa, and the time of the hot pressing molding is 1 hour to 2 hours.

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