Semiconductor coupling agent, preparation method thereof and application of semiconductor coupling agent in composite insulator

Abstract

The invention relates to the technical field of composite insulators, in particular to a semiconductor coupling agent, a preparation method of the semiconductor coupling agent and application of the semiconductor coupling agent in a composite insulator. The semiconductor coupling agent is prepared from the following raw materials in percentage by mass: 40 to 60 weight percent of silane coupling agent, 20 to 35 weight percent of conductive monomer, 5 to 15 weight percent of anti-aging agent, 3 to 8 weight percent of dispersing aid and 5 to 12 weight percent of organic solvent, wherein the total mass of the raw materials for preparing the semiconductor coupling agent is 100 percent. According to the semiconductor coupling agent provided by the invention, by optimizing the composition and content of each component, the synergistic consideration of interface bonding modification, precise semiconduction, local field intensity reduction, regulation and control functions and long-acting aging resistance is realized, and the semiconductor coupling agent can be widely applied to interface treatment of shielding layers and insulating layers in high-voltage and ultrahigh-voltage composite insulators; and the operation reliability and the full life cycle life of the composite insulator are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of composite insulator technology, and more particularly to a semiconductor coupling agent, its preparation method, and its application in composite insulators. Background Technology

[0002] Composite insulators have been widely replaced by traditional porcelain insulators in high-voltage power transmission systems due to their advantages of light weight, good pollution resistance, and high mechanical strength. Their internal insulation structure (referred to as "internal insulation") consists of three parts: a glass fiber reinforced epoxy resin core rod (bearing mechanical loads), a semi-conductive silicone rubber inner shielding layer (for uniform electric field), and a silicone rubber insulating layer (for main insulation). The quality of the interfacial bonding between these three parts and the semi-conductive stability of the inner shielding layer directly determine the operational reliability of the composite insulator.

[0003] In existing technologies, the internal insulation structure of composite insulators has three major problems: 1. Insufficient interfacial bonding: The material compatibility between the core rod (epoxy resin) and the inner shielding layer (silicone rubber) is poor. Ordinary coupling agents can only improve the bonding strength of a single interface and cannot simultaneously take into account the bonding strength of both the "core rod-shielding layer" and "shielding layer-insulation layer" interfaces. During long-term operation, interfacial peeling is prone to occur, causing local electric field concentration. 2. Difficulty in controlling semiconductor performance: The semiconductivity of the inner shielding layer mainly depends on the addition of fillers such as conductive carbon black and carbon fiber, but the fillers are prone to agglomeration, resulting in uneven resistivity distribution (fluctuation range can reach 10). 2 -10 6 (Ω·cm), causing electric field distortion. When the local field strength exceeds 5 kV / mm, it is easy to induce partial discharge and accelerate insulation aging. 3. Rapid decline in aging resistance: Composite insulators are exposed to outdoor ultraviolet, high temperature and humid environment for a long time. Existing coupling agents have no anti-aging function, which leads to a decrease in interfacial adhesion with aging time (the decrease rate can reach more than 30% after 1000 h of aging). At the same time, the resistivity of the shielding layer increases sharply, and the electric field uniformity is lost.

[0004] To address the aforementioned issues, current solutions often employ a composite approach combining coupling agents and conductive fillers. However, this approach suffers from problems such as poor carbon black dispersion leading to uneven resistivity and a lack of semiconducting properties. Existing solutions fail to achieve a synergistic balance between interfacial bonding, semiconducting regulation, and anti-aging effects. Therefore, there is an urgent need to develop a semiconductor coupling agent with multifunctional synergistic properties to fundamentally improve the performance of the internal insulation structure of composite insulators. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a semiconductor coupling agent, its preparation method, and its application in composite insulators. The semiconductor coupling agent provided by this invention, through optimization of the composition and content of each component, achieves a synergistic balance of interfacial bonding modification, precise semiconductivity reduction and local field intensity control, and long-term anti-aging effects. It can be widely used in the interface treatment of the inner shielding layer and insulation layer of high-voltage and ultra-high-voltage composite insulators, significantly improving the operational reliability and lifespan of composite insulators.

[0006] In a first aspect, the present invention provides a semiconductor coupling agent, wherein, based on the total mass of the raw materials for preparing the semiconductor coupling agent as 100%, the content of each raw material is as follows: Silane coupling agent 40-60 wt%; Conductive monomer 20-35wt%; Anti-aging agent 5-15wt%; Dispersant 3-8 wt%; Organic solvent 5-12wt%.

[0007] The silane coupling agent can be 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, etc.

[0008] The conductive monomer can be 20 wt%, 25 wt%, 30 wt%, 35 wt%, etc.

[0009] The anti-aging agent can be 5 wt%, 10 wt%, 15 wt%, etc.

[0010] The dispersing agent can be 3 wt%, 5 wt%, 8 wt%, etc.

[0011] The organic solvent can be 5 wt%, 8 wt%, 10 wt%, 12 wt%, etc.

[0012] The semiconductor coupling agent provided by this invention features a rationally designed composition and content of each component. Through the grafting reaction between the main silane coupling agent and the conductive monomer, the semiconductor coupling agent possesses both strong adhesion and precise semiconductivity. The addition of an anti-aging agent effectively extends the service life of the interface and shielding layer. Combined with dispersing agents and organic solvents, the components work synergistically to achieve a synergistic balance of interface bonding modification, precise semiconductivity reduction and local field intensity control, and long-term anti-aging. The semiconductor coupling agent provided by this invention can be widely used for interface treatment of the inner shielding layer and insulation layer of high-voltage and ultra-high-voltage composite insulators, significantly improving the operational reliability and lifespan of composite insulators. It solves the technical problems of weak interface bonding, electric field distortion, and aging resistance degradation in existing composite insulators.

[0013] As a preferred embodiment of the present invention, the silane coupling agent is selected from silane coupling agents containing amino or epoxy functional groups.

[0014] As the core binding component of semiconductor coupling agents, silane coupling agents containing amino or epoxy functional groups are selected. Among them, the amino group can undergo a condensation reaction with the hydroxyl group (-OH) on the surface of the mandrel, thereby achieving chemical bonding between the mandrel and the shielding layer, while the epoxy group can undergo an addition reaction with the vinyl group (-CH=CH2) in the silicone rubber, thereby achieving chemical bonding between the shielding layer and the insulating layer.

[0015] As a preferred embodiment of the present invention, the silane coupling agent is selected from γ-aminopropyltriethoxysilane (KH550) and / or γ-glycidoxypropyltrimethoxysilane (KH560), preferably a combination of γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane.

[0016] When the silane coupling agent provided by this invention is selected from a combination of γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, it can simultaneously achieve chemical bonding at the dual interfaces of "core rod-shielding layer" and "shielding layer-insulating layer", greatly improving the interface peel strength.

[0017] As a preferred embodiment of the present invention, the conductive monomer is selected from thiophene derivatives containing a conjugated structure, whose conjugated structure can form a conductive channel, thereby imparting semiconductivity to the semiconductor coupling agent.

[0018] As a preferred embodiment of the present invention, the solubility of the conductive monomer in an organic solvent is greater than or equal to 10 g / 100 mL, thereby ensuring compatibility with the silane coupling agent.

[0019] As a preferred embodiment of the present invention, the conductive monomer is selected from any one or more of 3,4-ethylenedioxythiophene (EDOT) or polythiophene oligomers with hydroxyl or carboxyl end groups.

[0020] As a preferred embodiment of the present invention, the molecular weight of the polythiophene oligomer with hydroxyl or carboxyl end groups is 500-2000, such as 500, 1000, 1500, 2000, etc.

[0021] This invention, by controlling the molecular weight (polythiophene oligomer 500-2000) and content of the conductive monomer, can precisely regulate the resistivity of the shielding layer to within 10. 3 -10 5 Ω·cm (optimal resistivity range of the inner shielding layer of composite insulators) avoids uneven electric field caused by excessively high or low resistivity, and is suitable for high voltage, ultra-high voltage and extra-high voltage power transmission scenarios.

[0022] As a preferred embodiment of the present invention, the anti-aging agent is selected from a combination of hindered amine light stabilizers (HALS) and ultraviolet light absorbers.

[0023] The anti-aging agent provided by this invention comprises HALS, which can capture free radicals and inhibit oxidative aging; and an ultraviolet light absorber, which can absorb ultraviolet light in the range of 280-400 nm, reducing the damage of ultraviolet light to interfacial bonding bonds. The synergistic effect of these two components enables the semiconductor coupling agent to maintain stable bonding and semiconducting properties even after 1000 h of aging.

[0024] As a preferred embodiment of the present invention, the mass ratio of the hindered amine light stabilizer to the ultraviolet light absorber is 1-3:1, for example, 1:1, 2:1, 3:1, etc.

[0025] As a preferred embodiment of the present invention, the hindered amine light stabilizer is selected from bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin 770) and / or bis(2,2,6,6-tetramethyl-4-piperidinyl) adipate (Tinuvin 622).

[0026] As a preferred embodiment of the present invention, the ultraviolet absorber is selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (Tinuvin P) and / or 2-hydroxy-4-methoxybenzophenone (UV-9).

[0027] As a preferred embodiment of the present invention, the dispersing agent is selected from polyether-modified silicone oil. The polyether segment in its molecular chain is compatible with the conjugated structure of the conductive monomer, and the silicone oil segment is compatible with silicone rubber, thereby effectively preventing the agglomeration of conductive monomer and ensuring uniform resistivity distribution (non-uniformity ≤15%).

[0028] As a preferred embodiment of the present invention, the polyether-modified silicone oil has a viscosity of 20-50 cSt at 25°C, such as 20 cSt, 30 cSt, 40 cSt, 50 cSt, etc.

[0029] As a preferred embodiment of the present invention, the organic solvent is selected from a mixed solution of anhydrous ethanol and ethyl acetate, which can dissolve the main silane coupling agent and anti-aging agent, and can also adjust the viscosity of the semiconductor coupling agent (15-30 cSt), facilitating the coating operation. Moreover, it can completely evaporate during the pre-curing process without leaving any residue.

[0030] As a preferred embodiment of the present invention, the volume ratio of anhydrous ethanol to ethyl acetate is 2-4:1, for example 2:1, 3:1, 4:1, etc.

[0031] As a preferred embodiment of the present invention, the semiconductor coupling agent has a viscosity of 15-30 cSt at 25°C, which facilitates the coating process.

[0032] In a second aspect, the present invention provides a method for preparing the semiconductor coupling agent described in the first aspect, the method comprising the following steps: (1) Mix the silane coupling agent and the organic solvent to obtain a premixed solution; (2) The conductive monomer is added to the premixed solution to carry out a grafting reaction to obtain a solution containing the grafting intermediate; (3) Add the anti-aging agent and dispersant to the solution containing the grafting intermediate for a heat preservation reaction, cool down, filter to remove insoluble matter, and obtain the semiconductor coupling agent.

[0033] The preparation method provided by this invention is simple and requires no special equipment. Through the preparation process of "premixed modification-functional composite-dispersion stabilization", the synergistic effect of each component is achieved. The prepared semiconductor coupling agent achieves a synergistic balance of interfacial bonding modification, precise semiconductivity reduction and local field intensity control function, and long-term anti-aging function. It is especially suitable for composite insulators for high voltage and ultra-high voltage transmission lines and substations.

[0034] The semiconductor coupling agent prepared by this invention is transparent or pale yellow, with a viscosity of 15-30 cSt at 25°C and a solid content of ≥88%. After meeting the standards, it is sealed and stored (0-40°C, protected from light).

[0035] As a preferred technical solution of the present invention, the mixing in step (1) is carried out under normal temperature stirring conditions, the stirring rate is 300-500 r / min, such as 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc., and the stirring time is 15-25 min, such as 15 min, 18 min, 20 min, 22 min, 25 min, etc.

[0036] As a preferred technical solution of the present invention, the conductive monomer in step (2) is added to the premixed liquid by dripping to avoid excessive local concentration leading to agglomeration.

[0037] As a preferred embodiment of the present invention, the dropping rate is 0.5-1 mL / min, for example, 0.5 mL / min, 0.6 mL / min, 0.7 mL / min, 0.8 mL / min, 0.9 mL / min, 1 mL / min, etc.

[0038] As a preferred embodiment of the present invention, the temperature of the grafting reaction is 50-60℃, such as 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, etc.; the grafting reaction time is 2-3h, such as 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, etc.

[0039] As a preferred embodiment of the present invention, the heat preservation reaction in step (3) is carried out under the protection of an inert gas to prevent oxidation of the anti-aging agent. The inert gas is selected from nitrogen, and the gas flow rate is 0.5-1 L / min, such as 0.5 L / min, 0.8 L / min, 1 L / min, etc.

[0040] As a preferred embodiment of the present invention, the temperature of the heat preservation reaction is 65-75℃, such as 65℃, 68℃, 70℃, 72℃, 75℃, etc.; the time of the heat preservation reaction is 1.5-2.5h, such as 1.5h, 1.8h, 2h, 2.2h, 2.5h, etc.

[0041] As a preferred embodiment of the present invention, the heat preservation reaction is carried out under stirring at a stirring rate of 600-800 r / min, such as 600 r / min, 650 r / min, 700 r / min, 750 r / min, 800 r / min, etc.

[0042] As a preferred technical solution of the present invention, step (3) involves cooling the temperature to 25-30°C.

[0043] As a preferred technical solution of the present invention, the insoluble matter is removed by filtering with a filter screen in step (3), and the pore size of the filter screen is 0.22 μm.

[0044] Thirdly, the present invention provides the application of the semiconductor coupling agent as described in the first aspect or the semiconductor coupling agent prepared by the preparation method described in the second aspect in composite insulators.

[0045] The semiconductor coupling agent provided by this invention can be applied to composite insulators, especially to the interface modification of the "core rod-inner shielding layer-silicone rubber insulation layer" of composite insulators.

[0046] Fourthly, the present invention provides an insulator for a composite insulator, the insulator comprising a core rod and a shed sheath covering the surface of the core rod; The core rod is a glass fiber reinforced epoxy resin core rod; The umbrella skirt sheath includes a sheath covering the core rod and a plurality of spaced umbrella skirts located on the outer periphery of the sheath; The sheath comprises, from the inside out, a first semiconductor coupling agent coating, a semiconductive silicone rubber inner shielding layer, a second semiconductor coupling agent coating, and a silicone rubber insulating layer. The first semiconductor coupling agent coating and the second semiconductor coupling agent coating each independently include the semiconductor coupling agent described in the first aspect or the semiconductor coupling agent prepared by the preparation method described in the second aspect.

[0047] As a preferred embodiment of the present invention, the semiconductive silicone rubber inner shielding layer comprises 100 parts by weight of methyl vinyl silicone rubber, 30-50 parts by weight of conductive carbon black, 1.5-2 parts by weight of vulcanizing agent, and 0.8-1.2 parts by weight of co-vulcanizing agent.

[0048] The conductive carbon black can be 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, etc.

[0049] The vulcanizing agent can be 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight, 2 parts by weight, etc.

[0050] The vulcanizing agent can be 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, etc.

[0051] As a preferred embodiment of the present invention, the amount of conductive carbon black used is 40-45 parts by weight.

[0052] As a preferred embodiment of the present invention, the conductive carbon black has a particle size of 20-50 nm, such as 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0053] As a preferred embodiment of the present invention, the vulcanizing agent is selected from di-tert-butyl peroxide.

[0054] As a preferred embodiment of the present invention, the vulcanizing agent is selected from triallyl isocyanurate.

[0055] As a preferred embodiment of the present invention, the silicone rubber insulating layer comprises 100 parts by weight of methyl vinyl silicone rubber, 20-30 parts by weight of fumed silica, 1.2-1.8 parts by weight of vulcanizing agent, and 0.5-1 parts by weight of antioxidant.

[0056] The fumed silica can be in quantities of 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, etc.

[0057] The vulcanizing agent can be 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0058] The antioxidant can be 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, etc.

[0059] As a preferred embodiment of the present invention, the amount of fumed silica used is 25-28 parts by weight.

[0060] As a preferred embodiment of the present invention, the specific surface area of ​​the fumed silica is 200-300 m². 2 / g, for example 200 m 2 / g、220 m 2 / g、240 m 2 / g、260 m 2 / g、280 m 2 / g、300 m 2 / g etc.

[0061] As a preferred embodiment of the present invention, the vulcanizing agent is selected from di-tert-butyl peroxide.

[0062] As a preferred embodiment of the present invention, the antioxidant is selected from hindered phenolic antioxidants.

[0063] As a preferred embodiment of the present invention, the composition of the umbrella skirt is the same as that of the silicone rubber insulating layer.

[0064] As a preferred embodiment of the present invention, the thickness of the first semiconductor coupling agent coating is 5-15 μm, such as 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, etc.

[0065] As a preferred embodiment of the present invention, the thickness of the semiconductive silicone rubber inner shielding layer is 1.5-3 mm, such as 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc.

[0066] As a preferred embodiment of the present invention, the thickness of the second semiconductor coupling agent coating is 3-8 μm, such as 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc.

[0067] The composite insulator provided by this invention has the following performance indicators: (1) Interface performance: The peel strength between the core rod and the semi-conductive silicone rubber inner shielding layer is ≥8kN / m, and the peel strength between the semi-conductive silicone rubber inner shielding layer and the silicone rubber insulating layer is ≥6kN / m; (2) Semiconducting properties: The volume resistivity of the semiconducting silicone rubber inner shielding layer is 10. 3 -10 5 Ω·cm (25℃), resistivity non-uniformity ≤15%; (3) Insulation performance: Partial discharge quantity ≤3pC at 1.73 times rated voltage, dielectric loss tangent (25℃, 50Hz) ≤0.003; (4) Aging resistance: After 1000 h of ultraviolet aging (temperature 85℃, relative humidity 85%, irradiation intensity 0.71 W / (m²), the product was tested and tested. 2 After ·nm), the resistivity change rate of the semiconductive silicone rubber inner shielding layer is ≤15%, and the interface peel strength decrease rate is ≤20%.

[0068] Electric field simulation and physical performance testing were performed on the insulator of the composite insulator. If the maximum electric field exceeds 3 kV / mm or the peel strength is lower than the standard value, the content of conductive monomer in the semiconductor coupling agent (±2-5 wt%) or the coating thickness (±2-3 μm) can be adjusted until the performance meets the standard.

[0069] Fifthly, the present invention provides a method for preparing the insulator of the composite insulator described in the fourth aspect, the method comprising the following steps: (1) The glass fiber reinforced epoxy resin core rod is pretreated, and then the first semiconductor coupling agent is coated on the surface of the glass fiber reinforced epoxy resin core rod to form a first semiconductor coupling agent coating, thereby obtaining the first composite insulator precursor. (2) A semiconductive silicone rubber inner shielding layer is laminated onto the surface of the first composite insulator precursor to obtain the second composite insulator precursor; (3) The second semiconductor coupling agent is coated on the surface of the second composite insulator precursor to form a second semiconductor coupling agent coating, thereby obtaining the third composite insulator precursor; (4) A silicone rubber insulating layer and a shed are laminated on the surface of the third composite insulator precursor to obtain the insulator of the composite insulator.

[0070] The insulator preparation process of the composite insulator provided by this invention is compatible with existing composite insulator production lines. It can directly use conventional equipment such as dip coating, molding, and vulcanization without modifying the production line, thus reducing the cost of industrial application.

[0071] As a preferred technical solution of the present invention, the pretreatment in step (1) includes: grinding the surface of the glass fiber reinforced epoxy resin mandrel to a roughness Ra of 0.8-1.6 μm, such as 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, etc., cleaning and drying, the cleaning agent used for cleaning is anhydrous ethanol; the drying temperature is 80-90℃, and the drying time is 30-45 min.

[0072] As a preferred embodiment of the present invention, the first semiconductor coupling agent and the second semiconductor coupling agent are further included in a pre-activation step before coating to ensure uniform dispersion of conductive monomers and avoid local resistivity fluctuations. The pre-activation method is as follows: constant temperature placement at 40-50℃ (e.g., 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, etc.) for 30-40 minutes (e.g., 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, etc.), while simultaneously ultrasonication at a frequency of 20-40kHz (e.g., 20 kHz, 25 kHz, 30 kHz, 35 kHz, 40 kHz, etc.) and a power of 300-500 W (e.g., 300 W, 350 W, 400 W, 450 W, 500 W, etc.) for 10-15 minutes (e.g., 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.).

[0073] As a preferred technical solution of the present invention, step (1) after coating the first semiconductor coupling agent onto the surface of the glass fiber reinforced epoxy resin mandrel further includes a pre-curing step, wherein the pre-curing temperature is 100-120℃ (e.g., 100℃, 105℃, 110℃, 115℃, 120℃, etc.) and the pre-curing time is 15-20 min (e.g., 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, etc.).

[0074] As a preferred embodiment of the present invention, the coating method is dip coating or spray coating.

[0075] As a preferred technical solution of the present invention, the composite method in step (2) is compression molding, with a molding temperature of 150-160℃ (e.g., 150℃, 155℃, 160℃, etc.), a pressure of 10-15 MPa (e.g., 10 MPa, 12 MPa, 15 MPa, etc.), and a holding time of 20-30 min (e.g., 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, etc.).

[0076] As a preferred technical solution of the present invention, step (3) after coating the second semiconductor coupling agent on the surface of the second composite insulator precursor further includes a pre-curing step, wherein the pre-curing temperature is 80-90℃ (e.g., 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, etc.) and the pre-curing time is 10-15 min (e.g., 10 min, 12 min, 14 min, 15 min, etc.).

[0077] As a preferred technical solution of the present invention, the composite method in step (4) is vulcanization molding, with a temperature of 160-170℃ (e.g., 160℃, 162℃, 164℃, 166℃, 168℃, 170℃, etc.), a pressure of 15-25 MPa (e.g., 15MPa, 18 MPa, 20 MPa, 22 MPa, 25 MPa, etc.), and a time of 25-35 min (e.g., 25 min, 28 min, 30 min, 32 min, 35 min, etc.).

[0078] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art: 1. The semiconductor coupling agent provided by this invention achieves a synergistic balance of interface bonding modification, precise semiconductivity reduction and local field intensity control, and long-term anti-aging by optimizing the composition and content of each component. It can be widely used in the interface treatment of the inner shielding layer and insulation layer of high voltage and ultra-high voltage composite insulators, significantly improving the operational reliability and lifespan of composite insulators.

[0079] 2. The composite insulator prepared using the semiconductor coupling agent provided by this invention has an insulator with an interfacial peel strength between the core rod and the shielding layer that is more than 45% higher than that of traditional coupling agents. The resistivity non-uniformity of the shielding layer is ≤15%, the partial discharge is ≤3 pC, and the performance degradation rate after 1000 h of aging is ≤20%. All indicators are superior to those of traditional coupling agents (peel strength is only 5-6 kN / m, and the degradation rate after aging is more than 30%). Attached Figure Description

[0080] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0081] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0082] Figure 1 This is a schematic diagram of the insulator structure of the composite insulator described in Application Example 1 of the present invention. Detailed Implementation

[0083] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0084] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0085] Example 1 This embodiment provides a semiconductor coupling agent and its preparation method. Taking the total mass of the raw materials for preparing the semiconductor coupling agent as 100%, the content of each raw material is as follows: 50wt% silane coupling agent, 30wt% conductive monomer, 10wt% anti-aging agent, 5wt% dispersant, 5wt% organic solvent; The silane coupling agent is a combination of KH550 and KH560 in a mass ratio of 1:1; the conductive monomer is a combination of EDOT and polythiophene oligomer (molecular weight 500-2000) in a mass ratio of 2:1; the anti-aging agent is a combination of Tinuvin770 and Tinuvin P in a mass ratio of 2:1; the dispersing aid is polyether-modified silicone oil; and the organic solvent is a mixed solution of anhydrous ethanol and ethyl acetate in a volume ratio of 3:1.

[0086] The preparation method includes the following steps: (1) Add 50 g of silane coupling agent and 5 g of organic solvent to the reaction vessel, stir at 25°C and 500 r / min for 15 min to obtain a premixed solution; (2) Add 30 g of conductive monomer dropwise to the premixed solution at a rate of 0.5 mL / min. After the addition is complete, raise the temperature to 60°C and keep it warm while stirring for 2 hours. (3) Add 10 g of anti-aging agent and 5 g of dispersant, heat to 65°C, stir at 700 r / min, introduce nitrogen gas at 0.5 L / min, and keep the reaction at the temperature for 2.5 h; (3) Cool down to 25°C, filter through a 0.22 μm filter membrane to obtain the semiconductor coupling agent. The viscosity was 25 cSt (25°C) and the solid content was 92%.

[0087] Example 2 This embodiment provides a semiconductor coupling agent and its preparation method. Taking the total mass of the raw materials for preparing the semiconductor coupling agent as 100%, the content of each raw material is as follows: 45 wt% silane coupling agent, 35 wt% conductive monomer, 12 wt% anti-aging agent, 5 wt% dispersant, and 3 wt% organic solvent; The silane coupling agent is a combination of KH550 and KH560 in a mass ratio of 1:1; the conductive monomer is a combination of EDOT and polythiophene oligomer (molecular weight 500-2000) in a mass ratio of 2:1; the anti-aging agent is a combination of Tinuvin770 and Tinuvin P in a mass ratio of 2:1; the dispersing aid is polyether-modified silicone oil; and the organic solvent is a mixed solution of anhydrous ethanol and ethyl acetate in a volume ratio of 3:1.

[0088] The preparation method includes the following steps: (1) Add 45g of silane coupling agent (KH550 22.5g + KH560 22.5g) and 3g of organic solvent (anhydrous ethanol and ethyl acetate in a volume ratio of 3:1) to the reaction vessel, stir at 30℃ and 400 r / min for 20 min to obtain a premixed solution; (2) Add 35 g of conductive monomer (23.3 g of EDOT + 11.7 g of polythiophene oligomer) dropwise to the premixed solution at a rate of 0.8 mL / min. After the addition is complete, raise the temperature to 55°C and keep it warm while stirring for 2.5 h. (3) Add 12 g of anti-aging agent (Tinuvin770 8g + Tinuvin P 4g) and 5 g of dispersant, heat to 70℃, stir at 800 r / min, introduce nitrogen gas at 0.8 L / min, and keep the reaction at this temperature for 2 h; (4) Cool down to 28°C, filter through a 0.22 μm filter membrane to obtain the semiconductor coupling agent. The viscosity was 22 cSt (25°C) and the solid content was 90%.

[0089] Example 3 This embodiment provides a semiconductor coupling agent and its preparation method. Taking the total mass of the raw materials for preparing the semiconductor coupling agent as 100%, the content of each raw material is as follows: 55 wt% silane coupling agent, 25 wt% conductive monomer, 8 wt% anti-aging agent, 7 wt% dispersant, 5 wt% organic solvent; The silane coupling agent is a combination of KH550 and KH560 in a mass ratio of 1:1; the conductive monomer is a combination of EDOT and polythiophene oligomer (molecular weight 500-2000) in a mass ratio of 2:1; the anti-aging agent is a combination of Tinuvin770 and Tinuvin P in a mass ratio of 2:1; the dispersing aid is polyether-modified silicone oil; and the organic solvent is a mixed solution of anhydrous ethanol and ethyl acetate in a volume ratio of 3:1.

[0090] The preparation method includes the following steps: (1) Add 55g of silane coupling agent and 5g of organic solvent to the reaction vessel, stir at 35℃ and 300 r / min for 25 min to obtain a premixed solution; (2) Add 25 g of conductive monomer to the premixed solution at a rate of 1 mL / min. After the addition is complete, raise the temperature to 50°C and keep it warm while stirring for 3 h. (3) Add 8 g of anti-aging agent and 7 g of dispersant, heat to 75°C, stir at 600 r / min, introduce nitrogen gas at 1 L / min, and keep the reaction at this temperature for 1.5 h; (4): Cool down to 30°C, filter through a 0.22 μm filter membrane to obtain the semiconductor coupling agent. The viscosity was 24 cSt (25°C) and the solid content was 93%.

[0091] Example 4 This embodiment provides a semiconductor coupling agent and its preparation method. Taking the total mass of the raw materials for preparing the semiconductor coupling agent as 100%, the content of each raw material is as follows: 60 wt% silane coupling agent, 20 wt% conductive monomer, 5 wt% anti-aging agent, 3 wt% dispersant, 12 wt% organic solvent; The silane coupling agent is KH550, the conductive monomer is polythiophene oligomer (molecular weight 500-2000), the anti-aging agent is a combination of Tinuvin 622 and UV-9 in a mass ratio of 2:1, the dispersing aid is polyether modified silicone oil, and the organic solvent is a mixed solution of anhydrous ethanol and ethyl acetate in a volume ratio of 2:1.

[0092] The preparation method is described in Example 2.

[0093] Comparative Example 1 This comparative example provides a silane coupling agent, KH550.

[0094] Comparative Example 2 This comparative example provides a silane coupling agent, which is obtained by mixing 80wt% KH560 and 20wt% carbon black micro powder.

[0095] Comparative Example 3 This comparative example provides a silane coupling agent, which is obtained by mixing 90wt% KH550 and 10wt% Tinuvin 622.

[0096] Application Example 1 This application example provides an insulator body for a composite insulator and a method for its preparation. A schematic diagram of the structure of the composite insulator body is shown below. Figure 1 As shown; The vulcanizing agent di-tert-butyl peroxide used in this application example was purchased from Nouryon, model Trigonox® B, and the hindered phenolic antioxidant was purchased from BASF, model Irganox® 1010; the preparation method includes the following steps: (1) Mandrel pretreatment: Grinding: Dry grind the surface of the glass fiber reinforced epoxy resin mandrel with 800-1000 grit sandpaper to achieve a surface roughness of Ra=0.8-1.6μm (increase the specific surface area and improve the adhesion of the coupling agent). Cleaning: Wipe the surface of the mandrel with anhydrous ethanol to remove grinding dust, then put it in an oven (80-90℃) to dry for 30-45 minutes to completely remove surface moisture (moisture will affect the condensation reaction between the coupling agent and the mandrel).

[0097] Coupling agent coating: Pre-activation: The semiconductor coupling agent prepared in Example 1 was placed in a constant temperature oven at 45°C for 35 min, and simultaneously subjected to ultrasonic vibration at 40 kHz and 300 W for 12 min to ensure uniform dispersion of conductive functional monomers. Coating: A 10μm thick coating is formed on the surface of the mandrel by spraying (spraying pressure 0.3-0.5 MPa); Pre-curing: The coated core rod is placed in an oven at 110°C for 18 min for pre-curing, so that the coupling agent and the surface of the core rod undergo a preliminary condensation reaction to form a stable first semiconductor coupling agent coating, thus obtaining the first composite insulator precursor.

[0098] (2) Preparation of the inner shielding layer: Preparation of rubber compound: Methyl vinyl silicone rubber (100 phr), conductive carbon black (45 phr), vulcanizing agent di-tert-butyl peroxide (1.5 phr), and co-vulcanizing agent triallyl isocyanurate (1.2 phr) are mixed according to the formula and kneaded on a two-roll mill at 550°C for 20 min to obtain a semi-conductive silicone rubber compound. Compression molding: The semi-conductive silicone rubber compound is coated on the surface of the first composite insulator precursor obtained in step (1), and placed in a mold for compression molding. The parameters are: temperature 155℃, pressure 12MPa, and heat preservation time 25 min, forming a 2.0 mm thick semi-conductive silicone rubber inner shielding layer, and obtaining the second composite insulator precursor.

[0099] (3) Secondary coating: The semiconductor coupling agent prepared in Example 1 is sprayed again on the surface of the second composite insulator precursor (coating thickness 5 μm), and pre-cured at 85°C for 12 min to enhance the interfacial bonding between the shielding layer and the insulation layer, forming a second semiconductor coupling agent coating, and obtaining the third composite insulator precursor; (4) Insulation layer coating: Insulation layer molding: A silicone rubber insulating compound (100 phr of methyl vinyl silicone rubber + 26 phr of fumed silica + 1.5 phr of di-tert-butyl peroxide vulcanizing agent + 0.8 phr of hindered phenolic antioxidant) is coated onto the front body of the third composite insulator. An integrated vulcanization molding process (1650℃, 20 MPa, 30 min) is used to form a silicone rubber insulating layer and a skirt, thus obtaining the insulator of the composite insulator.

[0100] Application Example 2-4 This application example provides an insulator for a composite insulator and a method for preparing the same. The preparation method is the same as that in Application Example 1, except that the semiconductor coupling agent prepared in Example 1 is replaced with the semiconductor coupling agents in Example 2 (Application Example 2), Example 3 (Application Example 3), and Example 4 (Application Example 4), respectively.

[0101] Comparative Application Examples 1-3 This comparative application example provides an insulator for a composite insulator and a method for preparing the same. The preparation method is the same as that in Application Example 1, except that the semiconductor coupling agent prepared in Example 1 is replaced with the coupling agents of Comparative Example 1 (Comparative Application Example 1), Comparative Example 2 (Comparative Application Example 2), and Comparative Example 3 (Comparative Application Example 3), respectively.

[0102] Performance Test 1 1. Interface peel strength: Tested according to DL / T 1573-2016 "Core Rods for Composite Insulators"; 2. Shielding layer volume resistivity: Tested according to GB / T 1410-2006 "Test methods for volume resistivity and surface resistivity of solid insulating materials"; 3. Partial discharge quantity: Tested according to GB / T 7354-2018 "High Voltage Testing Techniques - Partial Discharge Measurement"; 4. Aging resistance: Tested under UV aging conditions (1000h) according to GB / T 1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber".

[0103] The test results are shown in Table 1: Table 1

[0104] As can be seen from Table 1, the performance of the application examples is significantly better than that of the comparison application examples.

[0105] Among them, the interfacial peel strength is 30%-50% higher than that of the comparative application example, indicating that the semiconductor coupling agent provided by the present invention can effectively improve the adhesion between the two interfaces. Semiconductivity: The resistivity of the application example is uniform and stable, compared to the uneven resistivity caused by carbon black agglomeration in application example 2. Partial discharge level: ≤3pC in the application example, which is much lower than that in the comparative application example (≥8.5pC), indicating that the composite insulator prepared by the semiconductor coupling agent of the present invention has a more uniform electric field distribution; Aging resistance: The performance degradation rate of the application example after aging is ≤20%, while the resistivity change rate of application example 2 is 45%, indicating that the composite insulator prepared by the present invention has significant anti-aging effect.

[0106] Performance Test 2 Referring to Application Example 2, the semiconductor coupling agent prepared in Example 2 was applied to 110 kV, 500 kV, and 1000 kV composite insulators, respectively. By adjusting the content of conductive monomers in the semiconductor coupling agent (25 wt% in the 110 kV composite insulator, 30 wt% in the 500 kV composite insulator, and 35 wt% in the 1000 kV composite insulator; when the content of conductive monomers decreased, the content of the other components increased proportionally to make the total 100%), the resistivity of the shielding layer and the partial discharge were tested according to the test method in Performance Test 1. The results are shown in Table 2. Table 2

[0107] The results in Table 2 show that by adjusting the content of conductive monomers, the semiconductor coupling agent of the present invention can meet the requirements of composite insulators of different voltage levels, with partial discharge ≤2.5pC and uniform electric field distribution.

[0108] The semiconductor coupling agent provided by this invention has a simple preparation process, and the required raw materials (main silane coupling agent, conductive monomer, anti-aging agent, etc.) are all commercially available conventional products, and the cost is controllable. The application process is fully compatible with existing composite insulator production lines, requiring no additional equipment, and can be directly promoted for industrial use.

[0109] After adopting the semiconductor coupling agent of the present invention, the insulation performance of the composite insulator is significantly improved, and the service life can be extended to more than 25 years (approximately 15 years in the prior art). It can effectively reduce the operation and maintenance cost of high voltage transmission systems and has extremely high industrial practical value and economic value.

[0110] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0111] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A semiconductor coupling agent, characterized in that, Based on the total mass of the raw materials for preparing the semiconductor coupling agent being 100%, the content of each raw material is as follows: Silane coupling agent 40-60 wt%; Conductive monomer 20-35wt%; Anti-aging agent 5-15wt%; Dispersant 3-8 wt%; Organic solvent 5-12wt%.

2. The semiconductor coupling agent according to claim 1, characterized in that, The silane coupling agent is selected from silane coupling agents containing amino or epoxy functional groups, preferably γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane; And / or, the conductive monomer is selected from thiophene derivatives containing a conjugated structure, preferably the conductive monomer has a solubility in an organic solvent greater than or equal to 10 g / 100 mL; And / or, the anti-aging agent is selected from a combination of hindered amine light stabilizers and ultraviolet light absorbers, preferably the mass ratio of the hindered amine light stabilizer to the ultraviolet light absorber is 1-3:1; And / or, the dispersing agent is selected from polyether-modified silicone oil, preferably the polyether-modified silicone oil has a viscosity of 20-50 cSt at 25°C; And / or, the organic solvent is selected from a mixed solution of anhydrous ethanol and ethyl acetate; preferably, the volume ratio of anhydrous ethanol to ethyl acetate is 2-4:1; And / or, the viscosity of the semiconductor coupling agent at 25°C is 15-30 cSt.

3. The semiconductor coupling agent according to claim 2, characterized in that, The conductive monomer is selected from any one or more of 3,4-ethylenedioxythiophene or polythiophene oligomers with hydroxyl or carboxyl groups at the end; preferably, the molecular weight of the polythiophene oligomer with hydroxyl or carboxyl groups at the end is 500-2000. And / or, the hindered amine light stabilizer is selected from bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and / or bis(2,2,6,6-tetramethyl-4-piperidinyl) adipate; And / or, the ultraviolet absorber is selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and / or 2-hydroxy-4-methoxybenzophenone.

4. The method for preparing the semiconductor coupling agent according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Mix the silane coupling agent and the organic solvent to obtain a premixed solution; (2) The conductive monomer is added to the premixed solution to carry out a grafting reaction to obtain a solution containing the grafting intermediate; (3) Add the anti-aging agent and dispersant to the solution containing the grafting intermediate for a heat preservation reaction, cool down, filter to remove insoluble matter, and obtain the semiconductor coupling agent.

5. The preparation method according to claim 4, characterized in that, The conductive monomer described in step (2) is added to the premixed solution by dropping; preferably, the dropping rate is 0.5-1 mL / min. And / or, the grafting reaction temperature is 50-60℃, and the grafting reaction time is 2-3 h; And / or, the heat preservation reaction described in step (3) is carried out under the protection of an inert gas; And / or, the temperature of the heat preservation reaction is 65-75℃, and the time of the heat preservation reaction is 1.5-2.5 h.

6. The application of the semiconductor coupling agent as described in any one of claims 1-3 or the semiconductor coupling agent prepared by the preparation method described in claim 4 or 5 in composite insulators.

7. An insulator of a composite insulator, characterized in that, The insulator of the composite insulator includes a core rod and a shed sheath covering the surface of the core rod; The core rod is a glass fiber reinforced epoxy resin core rod; The umbrella skirt sheath includes a sheath covering the core rod and a plurality of spaced umbrella skirts located on the outer periphery of the sheath; The sheath comprises, from the inside out, a first semiconductor coupling agent coating, a semiconductive silicone rubber inner shielding layer, a second semiconductor coupling agent coating, and a silicone rubber insulating layer. The first semiconductor coupling agent coating and the second semiconductor coupling agent coating each independently include the semiconductor coupling agent as described in any one of claims 1-3 or the semiconductor coupling agent prepared by the preparation method described in claim 4 or 5.

8. The insulator of the composite insulator according to claim 7, characterized in that, The semi-conductive silicone rubber inner shielding layer comprises 100 parts by weight of methyl vinyl silicone rubber, 30-50 parts by weight of conductive carbon black, 1.5-2 parts by weight of vulcanizing agent, and 0.8-1.2 parts by weight of co-vulcanizing agent; preferably, the amount of conductive carbon black is 40-45 parts by weight, the particle size of the conductive carbon black is 20-50 nm, the vulcanizing agent is selected from di-tert-butyl peroxide, and the co-vulcanizing agent is selected from triallyl isocyanurate. And / or, the silicone rubber insulating layer comprises 100 parts by weight of methyl vinyl silicone rubber, 20-30 parts by weight of fumed silica, 1.2-1.8 parts by weight of vulcanizing agent, and 0.5-1 parts by weight of antioxidant; preferably, the amount of fumed silica is 25-28 parts by weight, and the specific surface area of ​​the fumed silica is 200-300 m². 2 / g, wherein the vulcanizing agent is selected from di-tert-butyl peroxide, and the antioxidant is selected from hindered phenolic antioxidants; And / or, the composition of the umbrella skirt is the same as the composition of the silicone rubber insulating layer; And / or, the thickness of the first semiconductor coupling agent coating is 5-15 μm; And / or, the thickness of the semiconductive silicone rubber inner shielding layer is 1.5-3 mm; And / or, the thickness of the second semiconductor coupling agent coating is 3-8 μm.

9. The method for preparing the insulator of the composite insulator as described in claim 7 or 8, characterized in that, The preparation method includes the following steps: (1) The glass fiber reinforced epoxy resin core rod is pretreated, and then the first semiconductor coupling agent is coated on the surface of the glass fiber reinforced epoxy resin core rod to form a first semiconductor coupling agent coating, thereby obtaining the first composite insulator precursor. (2) A semiconductive silicone rubber inner shielding layer is laminated onto the surface of the first composite insulator precursor to obtain the second composite insulator precursor; (3) The second semiconductor coupling agent is coated on the surface of the second composite insulator precursor to form a second semiconductor coupling agent coating, thereby obtaining the third composite insulator precursor; (4) A silicone rubber insulating layer and a shed are laminated on the surface of the third composite insulator precursor to obtain the insulator of the composite insulator.

10. The preparation method according to claim 9, characterized in that, The pretreatment in step (1) includes: grinding the surface of the glass fiber reinforced epoxy resin mandrel to a roughness Ra of 0.8-1.6 μm, and cleaning and drying; And / or, the first semiconductor coupling agent and the second semiconductor coupling agent further include a pre-activation step before coating, wherein the pre-activation method is: constant temperature placement at 40-50℃ for 30-40 min, and ultrasonication at a frequency of 20-40 kHz and a power of 300-500 W for 10-15 min. And / or, after the first semiconductor coupling agent is coated on the surface of the glass fiber reinforced epoxy resin mandrel in step (1), a pre-curing step is also included, wherein the pre-curing temperature is 100-120℃ and the pre-curing time is 15-20 min. And / or, the composite method described in step (2) is compression molding, with a molding temperature of 150-160℃, a pressure of 10-15MPa, and a holding time of 20-30 min; And / or, after applying the second semiconductor coupling agent to the surface of the second composite insulator precursor in step (3), a pre-curing step is also included, wherein the pre-curing temperature is 80-90℃ and the pre-curing time is 10-15 min; And / or, the composite method described in step (4) is vulcanization molding, with a temperature of 160-170℃, a pressure of 15-25 MPa, and a time of 25-35 min.

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