A semi-conductive buffer layer material, its preparation method and application

Abstract

The present invention provides a semi-conductive buffer layer material, a preparation method thereof and an application. According to the semi-conductive buffer layer material of the present invention, the raw materials for preparing the semi-conductive buffer layer material include: a matrix resin, a flexible resin, an acid anhydride curing agent, an amine accelerator, a conductive filler and a polysulfide rubber. The semi-conductive buffer layer material improves toughness while maintaining strength. In a low-temperature environment, the material has good toughness and does not crack. During the high-low temperature cycling process, when used between an insulating body and a metal casing, the material can avoid damage to the insulating body caused by the thermal expansion and contraction of the buffer layer. The present invention also provides a preparation method and an application of the semi-conductive buffer layer material.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power materials, and particularly relates to a semiconductive buffer layer material, a preparation method thereof, and an application thereof. Background Art

[0002] For high-voltage power cables of 66 kV and above, a metal sheath shielding structure is basically adopted. The semiconductive buffer layer is located between the extruded insulating core and the metal sheath, and is generally made by a winding process. As a component unit for the transition from high potential to low potential inside the cable and from insulation to metal grounding, the semiconductive buffer layer can achieve continuous and effective grounding of the insulating core axially.

[0003] The performance requirements and functions of the semiconductive buffer layer include: (1) Electrical performance: The buffer layer should be semiconductive to maintain good electrical contact between the insulating semiconductive shielding layer and the metal shielding layer, and the indicators should meet the requirements of relevant national standards; (2) Longitudinal water-blocking performance: If the cable has a longitudinal water-blocking requirement, there should be a longitudinal water-blocking layer between the insulating shielding layer and the radial metal waterproof layer to prevent water from extending longitudinally along the cable when the cable is damaged; (3) Thermal expansion buffering: The thickness of the buffer layer should meet the requirements of thermal expansion during cable operation.

[0004] At present, the semiconductive buffer layer material between the insulating main body and the metal shell is hard and brittle, with poor low-temperature toughness, and is prone to cracking with the change of ambient temperature. More seriously, it will peel off from the metal shell / insulating main body, resulting in damage to the insulating main body and the generation of microcracks inside, and finally showing discharge during the partial discharge test. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems in the prior art. For this purpose, the present invention provides a semiconductive buffer layer material, which improves toughness while maintaining strength. In a low-temperature environment, the material has good toughness and does not crack. During the high-low temperature cycle, when used between the insulating main body and the metal shell, the material can avoid damage to the insulating main body caused by the thermal expansion and contraction of the buffer layer.

[0006] The present invention also provides a method for preparing a semiconductive buffer layer material.

[0007] The present invention also provides an application of a semiconductive buffer layer material in high-voltage and / or extra-high-voltage prefabricated parts.

[0008] The first aspect of the present invention provides a semiconductive buffer layer material, and the preparation raw materials of the semiconductive buffer layer material include: matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polysulfide rubber.

[0009] One technical solution in the technical solution of the semi-conductive buffer layer material of the present invention has at least the following beneficial effects:

[0010] For the semi-conductive buffer layer material of the present invention, under the combined action of matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber, while improving the toughness of the material, the strength of the material is maintained, and a buffer material that is both tough and strong is obtained. At low temperatures, the material has good toughness and does not crack. During the high and low temperature cycling process, the material can avoid damage to the insulation body caused by the thermal expansion and contraction of the buffer layer. When using the semi-conductive buffer layer material of the present invention, when the environmental temperature changes greatly, the material does not peel off from the metal shell / insulation body.

[0011] According to some embodiments of the present invention, the matrix resin includes at least one of E-51 epoxy resin, E-44 epoxy resin, CYD-128 epoxy resin and 6101 epoxy resin.

[0012] Epoxy resin is a thermosetting resin. When the main agent and the hardener are properly mixed in a certain proportion and cross-linked and hardened, a three-dimensional network structure is formed, which can endow the product with special physical properties, mechanical properties and chemical resistance, etc. E-51 epoxy resin has a high epoxy value, low viscosity and light color, and can be used as adhesives, solvent-free coatings, self-leveling floor materials and casting materials, etc.

[0013] In the present invention, the role of the matrix resin is to react with the curing agent to form a three-dimensional network structure and provide the strength of the material.

[0014] According to some embodiments of the present invention, the flexible resin includes LER-0350 flexible epoxy resin.

[0015] The flexible epoxy resin with the brand number LER-0350 has a flexible and elastic cured product with a high elongation rate, and at the same time has a series of excellent properties of epoxy resin, especially chemical resistance, electrical insulation properties, high bonding strength and mechanical strength. This flexible epoxy resin changes the internal stress, brittleness and cracking problems of the cured product of the traditional bisphenol A epoxy resin and acid formulation system, endows the epoxy resin cured product with a flexible elastomer, solves the stress cracking phenomenon of the epoxy resin-anhydride system cured product, and enables the cast electrical components and electronic components to operate normally under alternating cold and hot temperatures.

[0016] In addition, LER-0350 flexible epoxy resin has very good compatibility with ordinary bisphenol A epoxy resin. Transparent and uniform liquids can be obtained after mixing in various proportions, and the viscosity of the mixture can be reduced, and the flexibility and elasticity of the cured product can be adjusted. LER-0350 flexible epoxy resin can be cured at room temperature with traditional amine curing agents or cured at medium temperature with aromatic amine and imidazole curing agents, or can also be cured with methyltetrahydrophthalic anhydride, and flexible and elastic cured products can be obtained, and they have good mechanical, physical and electrical properties.

[0017] LER-0350 flexible epoxy resin can greatly improve the flexibility, elongation and impact strength of the cured product.

[0018] According to some embodiments of the present invention, the flexible resin further includes at least one of DER 732P, DER 736 and DER 791.

[0019] According to some embodiments of the present invention, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride.

[0020] Methyltetrahydrophthalic anhydride, also known as methyltetrahydrophthalic anhydride, is a pale yellow transparent oily liquid and an important intermediate in the fields of electronic information materials, medicine, pesticides, resins, etc. At the same time, it can also be used in industries such as coatings, plasticizers, and pesticides. It is an important intermediate in the fields of electronic information materials, medicine, pesticides, resins, and national defense industry. Methyltetrahydrophthalic anhydride has the characteristics of low melting point, low toxicity, and low volatility, is convenient to use, has high reactivity and good miscibility with epoxy resin, and the cured product of epoxy resin using this curing agent has excellent electrical insulation performance and mechanical properties.

[0021] The semi-conductive buffer layer material of the present invention uses an anhydride curing agent, and can significantly improve the strength of the material without reducing the toughness, achieving the purpose of being both tough and strong.

[0022] According to some embodiments of the present invention, the polysulfide rubber includes at least one of JLY-121, JLY-124, JLY-155 and JLY-215.

[0023] Polysulfide rubber is a synthetic rubber obtained by polycondensing dihaloalkane with polysulfide of alkali metal or alkaline earth metal. It has excellent oil and solvent resistance, but has low strength, poor aging resistance, poor processing performance, and has an odor. It is mostly used in combination with nitrile rubber. Industrial products include solid polysulfide rubber, liquid polysulfide rubber and polysulfide latex. It is mainly used as a sealing material for construction, laminated glass and other industrial uses, as well as a curing agent for epoxy resin.

[0024] In the present invention, one of the functions of the polysulfide rubber is to act as a toughening agent, which can react with the epoxy resin to significantly improve the flexibility of the epoxy resin.

[0025] According to some embodiments of the present invention, the conductive filler includes carbon black.

[0026] According to some embodiments of the present invention, the raw materials for preparing the semi-conductive buffer layer material include, by weight:

[0027] Matrix resin: 100 parts;

[0028] Flexible resin: 120 parts to 150 parts;

[0029] Anhydride curing agent: 80 parts to 100 parts;

[0030] Amine accelerator: 1 part to 8 parts;

[0031] Conductive filler: 5 parts to 10 parts;

[0032] Polysulfide rubber: 80 parts to 100 parts.

[0033] According to some embodiments of the present invention, the raw materials for preparing the semi-conductive buffer layer material include, by weight:

[0034] Matrix resin: 100 parts;

[0035] Flexible resin: 150 parts;

[0036] Anhydride curing agent: 100 parts;

[0037] Amine accelerator: 5 parts to 8 parts;

[0038] Conductive filler: 8 parts to 10 parts;

[0039] Polysulfide rubber: 100 parts.

[0040] The second aspect of the present invention provides a method for preparing the semi-conductive buffer layer material, the method comprising mixing the matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber in proportion, stirring and degassing, then heating and curing, and cooling to obtain the semi-conductive buffer layer material.

[0041] One technical solution in the method for preparing the semi-conductive buffer layer material of the present invention has at least the following beneficial effects:

[0042] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are easy to obtain, the production cost is low, and it is easy to industrialize the production.

[0043] According to some embodiments of the present invention, the matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polysulfide rubber are mixed evenly in proportion, and the stirring time is 15 min to 30 min.

[0044] According to some embodiments of the present invention, the matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polysulfide rubber are mixed evenly in proportion, and the stirring time is 20 min to 30 min.

[0045] According to some embodiments of the present invention, the stirring speed is 250 to 300 rpm.

[0046] According to some embodiments of the present invention, the raw materials are mixed evenly, and during the stirring process, the temperature is 20°C to 40°C.

[0047] According to some embodiments of the present invention, the raw materials are mixed evenly, and during the stirring process, the relative humidity is controlled below 60% RH.

[0048] According to some embodiments of the present invention, the degassing method is: using a vacuum pump to evacuate the material.

[0049] According to some embodiments of the present invention, the degassing time is 40 min to 60 min.

[0050] According to some embodiments of the present invention, the degassing time is 50 min to 60 min.

[0051] According to some embodiments of the present invention, during heat curing, the degassed material is potted into a mold, and it can be heat cured in a forced-air heating oven.

[0052] According to some embodiments of the present invention, the temperature of the heat curing is 60°C to 80°C; and / or, the time of the heat curing is 8 h to 12 h.

[0053] According to some embodiments of the present invention, the temperature of the heat curing is 60°C to 70°C; and / or, the time of the heat curing is 8 h to 10 h.

[0054] According to some embodiments of the present invention, the cooling rate is 0.05°C / min to 0.15°C / min.

[0055] According to some embodiments of the present invention, the cooling rate is 0.05°C / min to 0.1°C / min.

[0056] Controlling a lower cooling rate can fully release the internal stress of the cured semi-conductive buffer layer material. If the cooling rate is too fast, stress concentration points will form inside the material, and it is prone to cracking during the thermal cycling process.

[0057] The third aspect of the present invention provides the application of the described semi-conductive buffer layer material in high-voltage and / or extra-high-voltage prefabricated parts.

[0058] The present invention relates to the application of a semi-conductive buffer layer material in high-voltage and / or extra-high-voltage prefabricated parts, and has at least the following beneficial effects:

[0059] When the semi-conductive buffer layer material of the present invention is used in high-voltage and / or extra-high-voltage prefabricated parts, due to the combined action of the semi-conductive buffer layer material with the matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polysulfide rubber, while improving the toughness of the material, the strength of the material is maintained, resulting in a buffer material that is both tough and strong. At low temperatures, the material has good toughness and does not crack. During the high-low temperature cycling process, the material can avoid damage to the insulating body caused by the thermal expansion and contraction of the buffer layer. When using the semi-conductive buffer layer material of the present invention, when the environmental temperature changes greatly, the material does not peel off from the metal shell / insulating body.

[0060] According to some embodiments of the present invention, the extra-high-voltage prefabricated part refers to a prefabricated part of 220 kV to 500 kV.

[0061] According to some embodiments of the present invention, the high-voltage prefabricated part refers to a prefabricated part of ≤110 kV.

[0062] According to some embodiments of the present invention, the prefabricated part includes a prefabricated insulating part joint.

[0063] The prefabricated insulating part joint includes an integral prefabricated rubber insulating part joint and a combined prefabricated insulating part intermediate joint.

[0064] The integral prefabricated rubber insulating part joint generally uses silicone rubber as the raw material, has good sealing performance and reliable insulating performance compared with the old-fashioned porcelain sleeve type terminal, has a small partial discharge value during long-term normal operation, a large surface leakage distance, and strong pollution resistance to ensure safe operation under harsh conditions and high pollution environments. The integral prefabricated rubber insulating part joint is manufactured by one-time compression molding, and will not produce the phenomenon that the creepage distance suddenly decreases due to the segmentation of the terminal body in the split type terminal. The integral prefabricated rubber insulating part joint is simple to install, small in size and light in weight, and suitable for installation at any angle. It will not cause damage caused by the explosion of cable accessories such as the old-fashioned porcelain sleeve terminal for some reason.

[0065] The combined prefabricated insulating joint for intermediate connection includes a prefabricated rubber stress cone and a prefabricated epoxy insulating component, which are assembled on-site. Spring pressing is adopted to make a certain pressure between the interface of the prefabricated rubber stress cone and the cross-linked cable insulation and between the rubber stress cone and the interface of the prefabricated epoxy insulating component to maintain the electrical insulation strength of the interface. Due to the adoption of the spring mechanical pressing measure, a smaller interference fit can be adopted between the outer diameter of the cross-linked cable and the inner diameter of the prefabricated rubber stress cone. The rubber stress cone is relatively easy to be sleeved on the cross-linked cable insulation. And even after long-term operation, although the elastic modulus of the rubber stress cone will decrease to some extent, the required pressure of the interface can still be maintained by virtue of the spring pressing. The protective copper sleeve of the combined prefabricated insulating joint for intermediate connection and the cable metal sheath are sealed by burning lead, and an external waterproof protection box is used, in which waterproof glue is poured. The insulating structure of the combined prefabricated insulating joint for intermediate connection is stable. When a tight positioning device is adopted for the protection box of the intermediate connection, it can withstand the action of the thermal mechanical force imbalance of the cable conductors on both sides of the intermediate connection. For example, the cable transitions from direct burial to tunnel laying, or from direct burial to other laying conditions with position movement. Specific embodiments

[0066] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in combination with the embodiments, but the present invention is not limited to these embodiments.

[0067] In some embodiments of the present invention, a semi-conductive buffer layer material is provided. The preparation raw materials of the semi-conductive buffer layer material include: matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber.

[0068] It can be understood that, under the combined action of the matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber in the semi-conductive buffer layer material of the present invention, while improving the toughness of the material, the strength of the material is maintained, and a buffer material that is both tough and strong is obtained. In a low-temperature environment, the toughness of the material is good and cracking will not occur. During the high-low temperature cycle process, the material can avoid the damage caused by the thermal expansion and contraction of the buffer layer to the insulating main body. When the semi-conductive buffer layer material of the present invention is used, when the environmental temperature changes greatly, the material does not peel off from the metal shell / insulating main body.

[0069] In some embodiments of the present invention, the matrix resin includes at least one of E-51 epoxy resin, E-44 epoxy resin, CYD-128 epoxy resin and 6101 epoxy resin.

[0070] It should be noted that epoxy resin is a thermosetting resin. When the main agent and the hardener are properly mixed in a certain proportion and crosslinked and hardened, a three-dimensional network structure is formed, thus endowing the product with special physical properties, mechanical properties, chemical resistance, etc. E-51 epoxy resin has a high epoxy value, low viscosity, and light color, and can be used as adhesives, solvent-free coatings, self-leveling floor materials, casting materials, etc.

[0071] In the present invention, the role of the matrix resin is to react with the curing agent to form a three-dimensional network structure and provide the strength of the material.

[0072] In some embodiments of the present invention, the flexible resin includes LER-0350 flexible epoxy resin.

[0073] The cured product of the flexible epoxy resin with the brand number LER-0350 has flexibility, elasticity, and high elongation. At the same time, it has a series of excellent properties of epoxy resin, especially chemical resistance, electrical insulation performance, and high bonding strength and mechanical strength. This flexible epoxy resin changes the internal stress, brittleness, and cracking problems of the cured product of the traditional bisphenol A epoxy resin-acid formulation system, endows the cured product of epoxy resin with a flexible elastomer, solves the stress cracking phenomenon of the cured product of the epoxy resin-anhydride system, and enables the cast electrical components and electronic components to operate normally under alternating cold and hot temperatures.

[0074] In addition, LER-0350 flexible epoxy resin has very good compatibility with ordinary bisphenol A epoxy resin. Transparent and uniform liquids can be obtained after mixing in various proportions, and the viscosity of the mixture can be reduced, and the flexibility and elasticity of the cured product can be adjusted. LER-0350 flexible epoxy resin can be cured at room temperature with traditional amine curing agents or cured at medium temperature with aromatic amine and imidazole curing agents, and can also be cured with methyltetrahydrophthalic anhydride, and flexible and elastic cured products can be obtained, and have good mechanical, physical, and electrical properties.

[0075] LER-0350 flexible epoxy resin can greatly improve the flexibility, elongation, and impact resistance of the cured product.

[0076] In some embodiments of the present invention, the flexible resin further includes at least one of DER 732P, DER 736, and DER 791.

[0077] In some embodiments of the present invention, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride.

[0078] Methyltetrahydrophthalic anhydride, also known as methyltetrahydrophthalic anhydride, is a light yellow transparent oily liquid and an important intermediate in the fields of electronic information materials, medicine, pesticides, resins, etc. It can also be used in industries such as coatings, plasticizers, and pesticides. It is an important intermediate in electronic information materials, medicine, pesticides, resins, and the national defense industry. Methyltetrahydrophthalic anhydride has the characteristics of low melting point, low toxicity, and low volatility, is easy to use, has high reactivity and good miscibility with epoxy resins, and the cured products of epoxy resins using this curing agent have excellent electrical insulation properties and mechanical properties.

[0079] The semi-conductive buffer layer material of the present invention uses an acid anhydride curing agent, which can significantly improve the strength of the material without reducing the toughness, achieving the purpose of being both tough and strong.

[0080] In some embodiments of the present invention, the polysulfide rubber includes at least one of JLY-121, JLY-124, JLY-155, and JLY-215.

[0081] Polysulfide rubber is a synthetic rubber obtained by polycondensation of dihaloalkanes with polysulfides of alkali metals or alkaline earth metals. It has excellent oil and solvent resistance, but has low strength, poor aging resistance, poor processing performance, and a bad smell. It is often used in combination with nitrile rubber. Industrial products include solid polysulfide rubber, liquid polysulfide rubber, and polysulfide latex. It is mainly used as a sealing material for construction, laminated glass, and other industrial uses, as well as a curing agent for epoxy resins.

[0082] In the present invention, one of the functions of the polysulfide rubber is to act as a toughening agent, which can react with epoxy resins to significantly improve the flexibility of the epoxy resins.

[0083] In some embodiments of the present invention, the conductive filler includes carbon black.

[0084] In some embodiments of the present invention, the raw materials for preparing the semi-conductive buffer layer material include, by weight:

[0085] Matrix resin: 100 parts;

[0086] Flexible resin: 120 parts to 150 parts;

[0087] Acid anhydride curing agent: 80 parts to 100 parts;

[0088] Amine accelerator: 1 part to 8 parts;

[0089] Conductive filler: 5 parts to 10 parts;

[0090] Polysulfide rubber: 80 parts to 100 parts.

[0091] In some other embodiments of the present invention, the raw materials for preparing the semi-conductive buffer layer material include, by weight:

[0092] Matrix resin: 100 parts;

[0093] Flexible resin: 150 parts;

[0094] Anhydride curing agent: 100 parts;

[0095] Amine accelerator: 5 to 8 parts;

[0096] Conductive filler: 8 to 10 parts;

[0097] Polysulfide rubber: 100 parts.

[0098] In some other embodiments of the present invention, the raw materials for preparing the semi-conductive buffer layer material include, by weight:

[0099] Matrix resin: 100 parts;

[0100] Flexible resin: 150 parts;

[0101] Anhydride curing agent: 100 parts;

[0102] Amine accelerator: 5 parts;

[0103] Conductive filler: 8 parts;

[0104] Polysulfide rubber: 100 parts.

[0105] In some other embodiments of the present invention, the present invention provides a method for preparing the semi-conductive buffer layer material of the present invention. The method includes mixing the matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber in proportion, stirring and degassing, then heating and curing, and obtaining the semi-conductive buffer layer material of the present invention after cooling.

[0106] It can be understood that the preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are easily available, the production cost is low, and it is easy to be industrially produced.

[0107] In some embodiments of the present invention, the matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber are mixed in proportion, and the stirring time is 15 min to 30 min.

[0108] In some embodiments of the present invention, the matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber are mixed in proportion, and the stirring time is 20 min to 30 min.

[0109] In some embodiments of the present invention, the stirring speed is 250 - 300 rpm.

[0110] In some embodiments of the present invention, the raw materials are mixed evenly, and during the stirring process, the temperature is 20°C to 40°C.

[0111] In some embodiments of the present invention, the raw materials are mixed evenly, and during the stirring process, the relative humidity is controlled below 60%RH.

[0112] In some embodiments of the present invention, the degassing method is: using a vacuum pump to evacuate the material.

[0113] In some embodiments of the present invention, the degassing time is 40 min to 60 min.

[0114] In some embodiments of the present invention, the degassing time is 50 min to 60 min.

[0115] In some embodiments of the present invention, during heat curing, the degassed material is potted into a mold, and heat curing can be carried out in a forced-air heating oven.

[0116] In some embodiments of the present invention, the heat curing temperature is 60°C to 80°C; and / or, the heat curing time is 8 h to 12 h.

[0117] In some embodiments of the present invention, the heat curing temperature is 60°C to 70°C; and / or, the heat curing time is 8 h to 10 h.

[0118] In some embodiments of the present invention, the cooling rate is 0.05°C / min to 0.15°C / min.

[0119] In some embodiments of the present invention, the cooling rate is 0.05°C / min to 0.1°C / min.

[0120] Controlling a lower cooling rate can fully release the internal stress of the cured semi-conductive buffer layer material. If the cooling rate is too fast, stress concentration points will form inside the material, and cracking is likely to occur during the thermal cycling process.

[0121] In some other embodiments of the present invention, the present invention provides the application of the semi-conductive buffer layer material of the present invention in high-voltage and / or extra-high-voltage prefabricated parts.

[0122] It can be understood that when the semi-conductive buffer layer material of the present invention is used in high-voltage and / or extra-high-voltage prefabricated parts, due to the combined action of the semi-conductive buffer layer material, matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber, while improving the toughness of the material, the strength of the material is maintained, resulting in a buffer material that is both tough and strong. At low temperatures, the material has good toughness and does not crack. During the high and low temperature cycling process, the material can avoid damage to the insulating body caused by the thermal expansion and contraction of the buffer layer. When using the semi-conductive buffer layer material of the present invention, when the ambient temperature changes greatly, the material does not peel off from the metal shell / insulating body.

[0123] In some embodiments of the present invention, the extra-high-voltage prefabricated part refers to a prefabricated part of 220 kV to 500 kV.

[0124] In some embodiments of the present invention, the high-voltage prefabricated part refers to a prefabricated part of ≤110 kV.

[0125] In some embodiments of the present invention, the prefabricated part includes a prefabricated insulating part joint.

[0126] The prefabricated insulating part joint includes an integral prefabricated rubber insulating part joint and a combined prefabricated insulating part intermediate joint.

[0127] The integral prefabricated rubber insulating part joint generally uses silicone rubber as the raw material. Compared with the old-fashioned porcelain sleeve type terminal, it has good sealing performance and reliable insulation performance. Under long-term normal operation, the partial discharge value is small, the surface leakage distance is large, and the pollution resistance is strong to ensure safe operation under harsh conditions and high pollution environments. The integral prefabricated rubber insulating part joint is manufactured by one-time compression molding, and there will be no phenomenon that the creepage distance suddenly decreases due to the segmentation of the terminal body in the split type terminal. The integral prefabricated rubber insulating part joint is simple to install, small in size and light in weight, and suitable for installation at any angle. It will not cause damage caused by the explosion of cable accessories such as the old-fashioned porcelain sleeve terminal for some reason.

[0128] The combined prefabricated insulating joint for medium joints includes a prefabricated rubber stress cone and a prefabricated epoxy insulating part, which are assembled on site. Spring pressing is adopted to make a certain pressure between the interface of the prefabricated rubber stress cone and the cross-linked cable insulation and between the rubber stress cone and the interface of the prefabricated epoxy insulating part to maintain the electrical insulation strength of the interface. Due to the adoption of spring mechanical pressing measures, a smaller interference fit can be adopted between the outer diameter of the cross-linked cable and the inner diameter of the prefabricated rubber stress cone. The rubber stress cone is easier to be sleeved on the cross-linked cable insulation. And even if the elastic modulus of the rubber stress cone decreases after long-term operation, the required pressure of the interface can still be maintained by spring pressing. The protective copper sleeve of the combined prefabricated insulating medium joint and the cable metal sheath are sealed by wiping lead, and an external waterproof protection box is used, in which waterproof glue is poured. The insulating structure of the combined prefabricated insulating part for medium joints is stable. When the protection box of the medium joint adopts a tight positioning device, it can withstand the action of the thermal mechanical force imbalance of the cable conductors on both sides of the medium joint. For example, when the cable transitions from direct burial to tunnel laying, or from direct burial to other radiation conditions with position movement.

[0129] The technical solution of the present invention will be better understood by combining with specific embodiments below.

[0130] Embodiment 1

[0131] This embodiment provides a semiconductive buffer layer material for between a high-voltage / extra-high-voltage combined prefabricated insulating body and a metal shell.

[0132] Calculated by weight parts, the preparation raw materials of the semiconductive buffer layer material include:

[0133] Matrix resin, i.e., E-51 epoxy resin: 100 parts;

[0134] Flexible resin, i.e., LER-0350 flexible epoxy resin: 150 parts;

[0135] Anhydride curing agent methyltetrahydrophthalic anhydride: 100 parts;

[0136] Amine accelerator DMP-30: 5 parts;

[0137] Conductive filler carbon black: 8 parts;

[0138] Polysulfide rubber JLY-121: 100 parts.

[0139] The preparation method of the semiconductive buffer layer material is specifically the following steps:

[0140] (1) At room temperature, mix each raw material according to the proportion and stir for 20 min to make the materials uniform. During this process, the temperature is controlled between 20 and 40 °C, and the relative humidity is kept below 60% RH;

[0141] (2) Carry out stirring and degassing treatment on the mixture, and the treatment time is 50 min;

[0142] (3) Pour the degassed material into a mold and cure it in a forced-air heating oven at 70 °C for 10 h;

[0143] (4) Cool it to room temperature in a forced-air oven at a cooling rate of 0.1 °C / min.

[0144] Comparative Example 1

[0145] This comparative example provides a semi-conductive buffer layer material for between a high-voltage / extra-high-voltage combined prefabricated insulation body and a metal shell.

[0146] By weight, the raw materials for preparing the semi-conductive buffer layer material include:

[0147] Matrix resin, i.e., E-51 epoxy resin: 100 parts;

[0148] Flexible resin, i.e., LER-0350 flexible epoxy resin: 200 parts;

[0149] Anhydride curing agent methyltetrahydrophthalic anhydride: 228 parts;

[0150] Amine accelerator DMP-30: 18 parts;

[0151] Conductive filler carbon black: 12 parts;

[0152] Reactive diluent CYDPG-660: 50 parts.

[0153] The preparation method of the semi-conductive buffer layer material is specifically the following steps:

[0154] (1) At room temperature, mix the raw materials in proportion and stir for 20 min to make the materials uniform. During this process, the temperature is controlled between 20 and 40 °C, and the relative humidity is maintained below 60% RH;

[0155] (2) Carry out a stirring and degassing treatment on the mixture for 50 min;

[0156] (3) Pour the degassed material into a mold and cure it in a forced-air heating oven at 60 °C for 10 h;

[0157] (4) Cool it to room temperature in a forced-air oven at a cooling rate of 0.1 °C / min.

[0158] Comparative Example 2

[0159] This comparative example provides a semi-conductive buffer layer material for between a high-voltage / extra-high-voltage combined prefabricated insulation body and a metal shell.

[0160] By weight, the raw materials for preparing the semi-conductive buffer layer material include:

[0161] The matrix resin, i.e., E-51 epoxy resin: 100 parts;

[0162] The flexible resin, i.e., LER-0350 flexible epoxy resin: 200 parts;

[0163] The curing agent T-31: 60 parts;

[0164] The filler is 115.5 parts, including 30 parts of alumina, 4.5 parts of carbon black and 80 parts of graphite;

[0165] The polysulfide rubber JLY-121: 30 parts;

[0166] The silane coupling agent KH-550: 5 parts.

[0167] The preparation method of the semi-conductive buffer layer material is specifically the following steps:

[0168] The preparation method of the above semi-conductive buffer layer material includes the following steps:

[0169] (1) At room temperature, mix the raw materials in proportion and stir for 20 min to make the materials uniform. During this process, the temperature is controlled between 20 and 40 °C, and the relative humidity is maintained below 60% RH;

[0170] (2) Carry out stirring and degassing treatment on the mixture for 50 min;

[0171] (3) Pour the degassed material into a mold and cure it in a forced-air heating oven at 80 °C for 8 h;

[0172] (4) Cool down to room temperature in a forced-air oven at a cooling rate of 0.1 °C / min.

[0173] Comparative Example 3

[0174] Based on Example 1, this comparative example provides a semi-conductive buffer layer material for between a high-voltage / extra-high-voltage combined prefabricated insulation body and a metal shell. By weight, the raw materials for preparing the semi-conductive buffer layer material include:

[0175] The matrix resin, i.e., E-51 epoxy resin: 100 parts;

[0176] The flexible resin, i.e., LER-0350 flexible epoxy resin: 150 parts;

[0177] The anhydride curing agent methyltetrahydrophthalic anhydride: 100 parts;

[0178] The amine accelerator DMP-30: 5 parts;

[0179] The conductive filler carbon black: 8 parts;

[0180] Polysulfide rubber JLY-121: 70 parts.

[0181] The preparation method of the semi-conductive buffer layer material is specifically as follows:

[0182] (1) At room temperature, mix the raw materials in proportion and stir for 20 min to make the materials uniform. During this process, the temperature is controlled between 20 and 40 °C, and the relative humidity is kept below 60% RH;

[0183] (2) Conduct stirring and degassing treatment on the mixture for 50 min;

[0184] (3) Pour the degassed material into a mold and cure it in a forced-air heating oven at 70 °C for 10 h;

[0185] (4) Cool down to room temperature at a cooling rate of 0.1 °C / min in a forced-air oven.

[0186] Comparative Example 4

[0187] Based on Example 1, this comparative example provides a semi-conductive buffer layer material for between a high-voltage / extra-high-voltage combined prefabricated insulating body and a metal shell.

[0188] By weight, the raw materials for preparing the semi-conductive buffer layer material include:

[0189] Matrix resin, i.e., E-51 epoxy resin: 100 parts;

[0190] Flexible resin, i.e., LER-0350 flexible epoxy resin: 100 parts;

[0191] Anhydride curing agent methyltetrahydrophthalic anhydride: 100 parts;

[0192] Amine accelerator DMP-30: 5 parts;

[0193] Conductive filler carbon black: 8 parts;

[0194] Polysulfide rubber JLY-121: 100 parts.

[0195] The preparation method of the semi-conductive buffer layer material is specifically as follows:

[0196] (1) At room temperature, mix the raw materials in proportion and stir for 20 min to make the materials uniform. During this process, the temperature is controlled between 20 and 40 °C, and the relative humidity is kept below 60% RH;

[0197] (2) Conduct stirring and degassing treatment on the mixture for 50 min;

[0198] (3) Pour the degassed material into a mold and cure it in a forced-air heating oven at 70 °C for 10 h;

[0199] (4) Cool down to room temperature in a blast drying oven at a rate of 0.1 °C / min.

[0200] The raw materials for Preparation Examples 1 and Comparative Examples 1 to 4 are shown in Table 1.

[0201] Table 1

[0202]

[0203] Performance Test 1: Anti-cracking performance experiment

[0204] Experimental group: 3 groups were set up in the experimental group, namely Experimental Groups 1 to 3. Samples were made from the semi-conductive buffer layer materials in Preparation Example 1 and Comparative Examples 1 and 2 for Experimental Groups 1 to 3 respectively. Each group had 5 samples, for a total of 15 samples. The sizes and appearances of all samples were the same.

[0205] Experimental method: Take the samples in Experimental Groups 1 to 3 and put them into a thermal cycling chamber. The heating and cooling rate is 0.3 °C / min, the cycling temperature range is -40 to 60 °C, and cycle for 10 periods. Observe whether the samples crack.

[0206] Performance Test 2: Mechanical property experiment

[0207] Experimental group: 3 groups were set up in the experimental group, namely Experimental Groups 1 to 3. Samples were made from the semi-conductive buffer layer materials in Preparation Example 1 and Comparative Examples 1 and 2 for Experimental Groups 1 to 3 respectively. Each group had 5 samples, for a total of 15 samples. The sizes and appearances of all samples were the same.

[0208] Experimental method: Under room temperature environment, the mechanical strength is carried out according to GB / T 2567-2021.

[0209] Performance Test 2: Adhesion property experiment

[0210] Experimental group: 6 groups were set up in the experimental group, namely Experimental Groups 1 to 6. Samples were made from the semi-conductive buffer layer materials in Preparation Example 1 and Comparative Examples 1 and 2 on the surface of epoxy resin for Experimental Groups 1 to 3; samples were made from the semi-conductive buffer layer materials in Preparation Example 1 and Comparative Examples 1 and 2 on the surface of metal copper for Experimental Groups 4 to 6. Each group had 5 samples, for a total of 30 samples. The sizes and appearances of all samples were the same.

[0211] Experimental method: Under room temperature environment, the adhesion property is carried out according to GB / T 9286-2021.

[0212] Table 2 Experimental results

[0213]

[0214] As can be seen from Table 2, the performance of the semi-conductive buffer layer material in Example 1 is the best. In Example 1, an acid anhydride curing agent is used, which can significantly improve the strength of the material without reducing the toughness, achieving the purpose of being both tough and strong.

[0215] In both Example 1 and Comparative Example 2, polythiol rubber that can react with epoxy resin is added, which can significantly improve the low-temperature toughness of the material system.

[0216] During the 10-cycle hot and cold cycling process, the anti-cracking performance of Example 1 and Comparative Example 2 is excellent. However, combining the results of Comparative Example 1, it can be seen that the strength of Comparative Example 1 is far inferior to that of Example 1, while the results of Example 1 show no obvious change. In summary, the material formula of Example 1 is the best formula.

[0217] The semi-conductive buffer layer material of the present invention, under the combined action of matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polythiol rubber, while improving the toughness of the material, maintains the strength of the material, obtaining a buffer material that is both tough and strong. In a low-temperature environment, the material has good toughness and does not crack. During the high and low temperature cycling process, the material can avoid damage to the insulation body caused by the thermal expansion and contraction of the buffer layer. When using the semi-conductive buffer layer material of the present invention, when the environmental temperature changes greatly, the material does not peel off from the metal shell / insulation body.

[0218] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are easily available, the production cost is low, and it is easy to industrialize the production.

[0219] When the semi-conductive buffer layer material of the present invention is used in high-voltage and / or extra-high-voltage prefabricated parts, due to the combined action of matrix resin, flexible resin, acid anhydride curing agent, amine accelerator, conductive filler, and polythiol rubber in the semi-conductive buffer layer material, while improving the toughness of the material, maintains the strength of the material, obtaining a buffer material that is both tough and strong. In a low-temperature environment, the material has good toughness and does not crack. During the high and low temperature cycling process, the material can avoid damage to the insulation body caused by the thermal expansion and contraction of the buffer layer. When using the semi-conductive buffer layer material of the present invention, when the environmental temperature changes greatly, the material does not peel off from the metal shell / insulation body.

[0220] Specifically, the extra-high-voltage prefabricated part refers to a prefabricated part of 220 kV to 500 kV, and the high-voltage prefabricated part refers to a prefabricated part of ≤110 kV.

[0221] The present invention has been described in detail above in combination with embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. Application of a semiconductive buffer layer material in high-voltage and / or extra-high-voltage prefabrications, characterized in that, The raw materials for preparing the semi-conductive buffer layer material include, by weight: Matrix resin: 100 parts; Flexible resin: 120 parts to 150 parts; Anhydride curing agent: 80 parts to 100 parts; Amine accelerator: 1 part to 8 parts; Conductive filler: 5 parts to 10 parts; Polysulfide rubber: 80 parts to 100 parts; The matrix resin includes at least one of E-51 epoxy resin, E-44 epoxy resin, CYD-128 epoxy resin and 6101 epoxy resin; The flexible resin includes at least one of LER-0350, DER 732P, DER 736 and DER 791; The anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride; The polysulfide rubber includes at least one of JLY-121, JLY-124, JLY-155 and JLY-215; The ultra-high voltage prefabricated component refers to a prefabricated component of 220 kV to 500 kV; The high voltage prefabricated component refers to a prefabricated component of ≤110 kV.

2. The application according to claim 1, characterized in that The method for preparing the semi-conductive buffer layer material includes mixing the matrix resin, flexible resin, anhydride curing agent, amine accelerator, conductive filler and polysulfide rubber in proportion, stirring and degassing, then heating and curing, and obtaining the semi-conductive buffer layer material after cooling.

3. The application according to claim 2, characterized in that, The temperature of the heating and curing is 60°C to 80°C.

4. The application according to claim 2, wherein The time of the heating and curing is 8 h to 12 h.

5. The application according to claim 2, wherein The cooling rate is 0.05°C / min to 0.15°C / min.

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