Novel high-strength light insulator and preparation method thereof

Abstract

The invention relates to the technical field of insulators, and provides a novel high-strength light insulator and a preparation method thereof. A novel high-strength light insulator comprises a core rod and fittings inserted into the two ends of the core rod, an umbrella skirt sheath is injected to the outer surface of the core rod, raw materials of the core rod comprise a sizing material and glass fibers, and the sizing material comprises, by weight, 100 parts of bisphenol A epoxy resin, 70-80 parts of a curing agent, 1-2 parts of an accelerant and 5-8 parts of filler; the curing agent comprises an alicyclic anhydride curing agent, an alicyclic amine curing agent and a polymercapto organic ester compound. According to the technical scheme, the problem of insufficient strength of a light insulator in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of insulator technology, specifically to a novel high-strength lightweight insulator and its preparation method. Background Technology

[0002] In power systems, epoxy resin composite insulators are widely used due to their combined advantages of insulation and lightweight design. However, their insufficient strength has long constrained the reliability of the power grid. The current low strength of these insulators mainly stems from inherent defects in the epoxy resin and curing agent system. Commonly used curing agents include amine curing agents and acid anhydride curing agents. Amine curing agents react quickly with epoxy resin and exhibit excellent low-temperature curing performance. However, the cross-linking network formed by aliphatic amine curing agents and epoxy resin is dominated by rigid amine bonds, resulting in weak molecular chain mobility. The cured adhesive layer is brittle, and when the insulator is subjected to mechanical loads, stress cannot be dispersed through chain segment slippage, easily concentrating at defects and causing cracking, thus affecting the insulator's bending strength. Acid anhydride curing agents, on the other hand, possess excellent insulation and aging resistance, but their low activity and poor miscibility with epoxy resin, coupled with long curing times, result in high hardness of the cured thermosetting product, making it prone to cracking under external temperature variations, severely impacting the insulator's strength.

[0003] Therefore, it is necessary to propose a new type of high-strength lightweight insulator and its preparation method. Summary of the Invention

[0004] This invention proposes a novel high-strength lightweight insulator and its preparation method, which solves the problem of insufficient strength of lightweight insulators in related technologies.

[0005] The technical solution of the present invention is as follows: The present invention proposes a novel high-strength lightweight insulator, comprising a core rod and fittings inserted into both ends of the core rod. The outer surface of the core rod is injection-molded with a shed sheath. The raw materials of the core rod include rubber and glass fiber. The rubber comprises the following components by weight: 100 parts of bisphenol A epoxy resin, 70-80 parts of curing agent, 1-2 parts of accelerator, and 5-8 parts of filler. The curing agent comprises alicyclic anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound.

[0006] The present invention adds an accelerator to the rubber compound of the lightweight insulator, which can accelerate the ring-opening esterification reaction of acid anhydride, form hydrogen bond complexes with alicyclic amines, regulate the reactivity of amine groups, avoid local over-crosslinking, promote the formation of a uniform and dense three-dimensional structure, and further improve the strength of the lightweight insulator.

[0007] As a further technical solution, the alicyclic anhydride curing agent includes one or more of tetrahydrophthalic anhydride, nadicol anhydride, and methylnadicol anhydride; preferably methylnadicol anhydride.

[0008] The curing agent in the adhesive of the lightweight insulator of this invention includes an alicyclic anhydride curing agent. The cyclic anhydride curing agent contains a cyclic structure, and its miscibility with epoxy resin is significantly better than that of traditional anhydride curing agents. Methylnadicosic anhydride is preferred. Methylnadicosic anhydride is a liquid and easy to use. The norbornene bicyclic skeleton it contains can form a highly regular three-dimensional cross-linked network after curing with epoxy resin. Moreover, the steric hindrance effect of the bicyclic structure makes the cross-linking points more evenly distributed in the matrix, which helps to improve the strength of the lightweight insulator.

[0009] As a further technical solution, the alicyclic amine curing agent includes one or more of isophorone diamine, montanane diamine, and o-diaminocyclohexane, preferably isophorone diamine.

[0010] The curing agent in the adhesive of the lightweight insulator of the present invention includes an alicyclic amine curing agent. The amine group of the alicyclic amine curing agent is linked to the alicyclic ring. Due to the steric hindrance effect of the alicyclic ring, the reactivity of its active hydrogen is slightly lower than that of aliphatic amines. The slower reaction rate allows the molecular chain to extend more fully before crosslinking. Furthermore, due to the presence of the alicyclic structure, the insulator can absorb energy through the torsional deformation of the ring when bent, avoiding brittle fracture caused by stress concentration, and further improving the strength of the lightweight insulator.

[0011] As a further technical solution, the polythiol organic ester compound includes one or more of ethylene glycol dithiocarbamate, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrathiocarbamate, preferably trimethylolpropane tris(3-mercaptopropionate).

[0012] The curing agent in the adhesive of the lightweight insulator of the present invention includes a polythiol organic ester compound, which contains multiple thiol active groups. The polythiol organic ester compound is preferably trimethylolpropane tris(3-mercaptopropionate). Trimethylolpropane tris(3-mercaptopropionate) contains a moderate number of thiol groups. When the number of thiol groups is too small, the active sites provided by the unit mass of the compound are insufficient, resulting in a slow curing reaction rate. Uncrosslinked epoxy groups are prone to forming linear molecular chain defects. If the number of thiol groups is too large, the excessively high thiol density will cause the curing reaction rate to run out of control, affecting the strength of the lightweight insulator. Therefore, trimethylolpropane tris(3-mercaptopropionate) is preferred, which can better improve the strength of the lightweight insulator.

[0013] As a further technical solution, the mass ratio of the alicyclic anhydride curing agent, the alicyclic amine curing agent, and the polythiol organic ester compound is 5:2:1~1.5.

[0014] In this invention, the mass ratio of alicyclic anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound in the adhesive of the lightweight insulator is 5:2:1~1.5. Among them, the alicyclic anhydride is used as the main curing agent, and its reaction with epoxy resin can form a regular network skeleton under the action of the accelerator. The amount of alicyclic amine curing agent added is moderate. The amino groups in the alicyclic amine curing agent undergo addition reaction with the epoxy groups of epoxy resin, introducing polar amine bonds into the crosslinking network. This not only enhances the network density through hydrogen bonding, but the presence of alicyclic rings can also reduce stress concentration points in the crosslinking network, thus improving the toughness of the initial skeleton. The polythiol organic ester compound is added in the smallest amount, but plays a key role in activity regulation and performance optimization. By regulating the activity of thiol groups, the reaction rate of the entire curing system is controlled within a suitable range. Moreover, the addition of thiol groups can further alleviate the problem of high brittleness of the adhesive layer caused by amine curing agents, and further improve the strength of the lightweight insulator.

[0015] As a further technical solution, the accelerator includes one or more of 2-ethyl-4-methylimidazole, 2,4,6-tris(dimethylaminomethyl)phenol, and N,N-dimethylaniline, preferably 2,4,6-tris(dimethylaminomethyl)phenol.

[0016] As a further technical solution, the filler comprises the following raw materials in parts by weight: 60-80 parts of alumina, 20-40 parts of silicon dioxide, and 8-10 parts of mercaptobenzamide compound.

[0017] The filler in the adhesive of the lightweight insulator of this invention includes alumina, which has excellent dielectric insulation properties and a stable crystal structure. It can form a uniform insulating barrier in an electric field, effectively preventing charge migration and increasing the breakdown voltage threshold of the material. Silica has a high dielectric property matching degree with the epoxy resin matrix, which can fill the micropores in the system, reduce air gap defects, make the electric field distribution more uniform, and reduce the risk of breakdown caused by local electric field concentration. The mercaptobenzamide compound can chemically react with the epoxy groups in the epoxy resin. At the same time, the polar structure of the benzamide group can form hydrogen bonds with the hydroxyl groups on the surface of alumina and silica, enhance the interfacial bonding force between the filler and the resin matrix, reduce air gaps or defects at the interface, avoid electric field concentration at the interface and prevent breakdown, and enhance the breakdown strength of the lightweight insulator.

[0018] As a further technical solution, the mercaptobenzamide compound includes one or two of 2-mercapto-N-methylbenzamide and N-(3-(5-mercapto-1H-tetrazole-1-yl)phenyl)benzamide, preferably 2-mercapto-N-methylbenzamide.

[0019] As a further technical solution, the preparation method of the filler includes the following steps: dispersing a mercaptobenzamide compound in anhydrous ethanol, adding alumina and silica, mixing and drying to obtain the filler.

[0020] As a further technical solution, the mixing time is 3 to 5 hours, for example, it can be 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, 4.2 hours, 4.5 hours, 4.8 hours, or 5 hours, preferably 3 hours.

[0021] As a further technical solution, the mass ratio of the alumina and silicon dioxide to anhydrous ethanol is 1:3 to 5, for example, it can be 1:3, 1:3.5, 1:4, 1:4.5, or 1:5, preferably 1:3.

[0022] As a further technical solution, the amount of the mercaptobenzamide compound added is 8% to 10% of the total mass of alumina and silica.

[0023] This invention proposes a method for preparing a novel high-strength lightweight insulator, comprising the following steps: S1. Mix the raw materials of the adhesive to obtain mixture A; S2. The glass fiber is introduced into the mold, the mixture A is injected, and the mixture is pultruded and then cured to obtain a mandrel; S3. Insert fittings into both ends of the core rod, and inject a skirt sheath onto the outer surface of the core rod to obtain a lightweight insulator.

[0024] The working principle and beneficial effects of this invention are as follows: In this invention, the curing agent in the adhesive compound of the high-strength lightweight insulator is a compound system of alicyclic acid anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound. By optimizing the crosslinking network, the strength of the insulator is improved. In the prior art, alicyclic amine curing agents for epoxy resin have the problem of excessive rigidity, while acid anhydride curing agents have low activity and poor miscibility with epoxy resin, which seriously affects the strength of the insulator. In this invention, the curing agent in the high-strength lightweight insulator is a compound system of alicyclic acid anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound. The alicyclic acid anhydride curing agent has good miscibility with epoxy resin, but poor activity. The presence of alicyclic rings in the alicyclic amine curing agent can limit excessive slippage of molecular chains through the ring structure and absorb external force energy through the torsion and deformation of the ring. It is less brittle than conventional aliphatic amine curing agents, but still relatively brittle when used alone. The thiol groups in the polythiol organic ester compound have high reactivity, which can make up for the poor activity of alicyclic acid anhydride curing agents. In addition, the addition of active thiol groups helps to enhance the flexibility of epoxy resin and further alleviate the problem of high brittleness of amine curing agent adhesive layers. The compound of the three further optimizes the crosslinking structure of epoxy resin and improves the strength of lightweight insulators. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] In the following examples and comparative examples: Bisphenol A epoxy resin: model E51 (618); Alumina: average particle size is 30 nm; Silica: average particle size is 50nm.

[0027] Example 1 A method for preparing a novel high-strength lightweight insulator includes the following steps: S1. Mix 100 parts of bisphenol A epoxy resin, 70 parts of curing agent, 1 part of 2,4,6-tris(dimethylaminomethyl)phenol and 5 parts of filler to obtain mixture A; S2. Glass fiber is introduced into a mold, mixture A is injected, pultruded and cured to obtain a mandrel; S3. Connect fittings to both ends of the core rod, and inject a skirt sheath onto the outer surface of the core rod to obtain a lightweight insulator. The curing agent is composed of methyl nadicarboxylic anhydride, isoflavone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 5:2:1; The filler consists of 60 parts alumina and 40 parts silica.

[0028] Example 2 A method for preparing a novel high-strength lightweight insulator includes the following steps: S1. Mix 100 parts of bisphenol A epoxy resin, 75 parts of curing agent, 1.5 parts of 2,4,6-tris(dimethylaminomethyl)phenol and 6 parts of filler to obtain mixture A; S2. Glass fiber is introduced into a mold, mixture A is injected, pultruded and cured to obtain a mandrel; S3. Connect fittings to both ends of the core rod, and inject a skirt sheath onto the outer surface of the core rod to obtain a lightweight insulator. The curing agent is composed of methyl nadicarboxylic anhydride, isoflavone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 5:2:1; The filler consists of 60 parts alumina and 40 parts silica.

[0029] Example 3 A method for preparing a novel high-strength lightweight insulator includes the following steps: S1. Mix 100 parts of bisphenol A epoxy resin, 80 parts of curing agent, 2 parts of 2,4,6-tris(dimethylaminomethyl)phenol and 8 parts of filler to obtain mixture A; S2. Glass fiber is introduced into a mold, mixture A is injected, pultruded and cured to obtain a mandrel; S3. Connect fittings to both ends of the core rod, and inject a skirt sheath onto the outer surface of the core rod to obtain a lightweight insulator. The curing agent is composed of methyl nadicarboxylic anhydride, isoflavone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 5:2:1; The filler consists of 60 parts alumina and 40 parts silica.

[0030] Example 4 The difference between Example 4 and Example 1 is that the curing agent is composed of methyl nadicarboxylic anhydride, isoflavone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 5:2:1.5.

[0031] Example 5 The difference between Example 5 and Example 4 is that ethylene glycol dimercaptoacetate is replaced with an equal amount of trimethylolpropane tris(3-mercaptopropionate).

[0032] Example 6 The difference between Example 6 and Example 4 is that ethylene glycol dimercaptoacetate is replaced with an equal amount of pentaerythritol tetramercaptoacetate.

[0033] Example 7 The preparation method of the filler includes the following steps: 8 parts of 2-mercapto-N-methylbenzamide are dispersed in 300 parts of anhydrous ethanol, 60 parts of alumina and 40 parts of silica are added, mixed for 3 hours and then dried to obtain the filler; The difference between Example 7 and Example 5 is that the filler is replaced with an equal amount of filler obtained by the above preparation method.

[0034] Example 8 The difference between Example 8 and Example 7 is that the amount of 2-mercapto-N-methylbenzamide added is 10 parts.

[0035] Example 9 The difference between Example 9 and Example 7 is that 2-mercapto-N-methylbenzamide is replaced with an equal amount of 3-mercapto-N-methylpropionamide.

[0036] Comparative Example 1 Compared with Example 1, Comparative Example 1 differs in that the curing agent is composed of methyl nadicarboxylic anhydride and isophorone diamine in a mass ratio of 5:2.

[0037] Comparative Example 2 Compared with Example 1, Comparative Example 2 differs in that the curing agent consists of methyl nadic anhydride and ethylene glycol dimercaptoacetate in a mass ratio of 5:1.

[0038] Comparative Example 3 Compared with Example 1, Comparative Example 3 differs in that the curing agent consists of isoflavone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 2:1.

[0039] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the curing agent is only methylnadicotinic anhydride.

[0040] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the curing agent is only isophorone diamine.

[0041] Experimental Example 1 The bending strength of the core rods in the novel high-strength lightweight insulators prepared in Examples 1-6 and Comparative Examples 1-5 was tested according to the test methods specified in DL / T1580-2021 "Technical Conditions for Cores of AC and DC Composite Insulators". The core rod diameter was 24 mm.

[0042] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-5

[0043] As shown in Table 1, when the curing agent includes alicyclic anhydrides, alicyclic amines and polythiol organic ester compounds, the bending strength of the insulator core rod can be improved.

[0044] Experiment Example 2 The breakdown strength of the core rods in the novel high-strength lightweight insulators prepared in Examples 5 and 7-9 was tested according to the test methods specified in DL / T 1580-2021 "Technical Conditions for Cores of AC and DC Composite Insulators".

[0045] The test results are shown in Table 2: Table 2 Performance test results of Examples 5 and 7-9

[0046] As shown in Table 2, the addition of mercaptobenzamide compounds to the filler can improve the breakdown strength of the insulator core rod.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A new type of high strength light weight insulator, characterized in that, The device includes a mandrel and fittings inserted into both ends of the mandrel. The outer surface of the mandrel is injection-molded with a skirt sheath. The raw materials of the mandrel include adhesive and glass fiber. The adhesive comprises the following components by weight: 100 parts of bisphenol A epoxy resin, 70-80 parts of curing agent, 1-2 parts of accelerator, and 5-8 parts of filler. The curing agent includes alicyclic anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound.

2. A new type of high-strength lightweight insulator according to claim 1, characterized in that, The alicyclic anhydride curing agent includes one or more of tetrahydrophthalic anhydride, nadikelic anhydride, and methylnadikelic anhydride.

3. A new type of high strength light weight insulator according to claim 1, characterized in that, The alicyclic amine curing agent includes one or more of isoflavone diamine, montanane diamine, and o-diaminocyclohexane.

4. A new type of high strength light weight insulator according to claim 1, characterized in that, The polythiol organic ester compounds include one or more of ethylene glycol dithiocarbamate, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrathiocarbamate.

5. A new type of high strength light weight insulator according to claim 1, characterized in that, The mass ratio of the alicyclic anhydride curing agent, the alicyclic amine curing agent, and the polythiol organic ester compound is 5:2:1~1.

5.

6. A new type of high strength light weight insulator according to claim 1, characterized in that, The accelerator includes one or more of 2-ethyl-4-methylimidazole, 2,4,6-tris(dimethylaminomethyl)phenol, and N,N-dimethylaniline.

7. A new type of high strength light weight insulator according to claim 1, characterized in that, The filler comprises the following raw materials in parts by weight: 60-80 parts alumina, 20-40 parts silica, and 8-10 parts mercaptobenzamide compound.

8. A new type of high strength lightweight insulator according to claim 7, characterized in that, The mercaptobenzamide compound includes one or both of 2-mercapto-N-methylbenzamide and N-(3-(5-mercapto-1H-tetrazole-1-yl)phenyl)benzamide.

9. A new type of high strength light weight insulator according to claim 7, characterized in that, The preparation method of the filler includes the following steps: dispersing a mercaptobenzamide compound in anhydrous ethanol, adding alumina and silica, mixing and drying to obtain the filler.

10. A method for preparing a novel high-strength lightweight insulator, used to prepare the novel high-strength lightweight insulator according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Mix the raw materials of the adhesive to obtain mixture A; S2. The glass fiber is introduced into the mold, the mixture A is injected, and the mixture is pultruded and then cured to obtain a mandrel; S3. Insert fittings into both ends of the core rod, and inject a skirt sheath onto the outer surface of the core rod to obtain a lightweight insulator.

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