A high-strength light-weight insulator and a method for manufacturing the same

Abstract

The application relates to the technical field of insulators, and discloses a high-strength light insulator and a preparation method thereof. The high-strength light insulator comprises a core rod and a fitting on both ends of the core rod, an umbrella skirt sheath is injected on the outer surface of the core rod, and the raw material of the core rod comprises glue and glass fibers; the glue comprises the following raw material components in parts by weight: 100 parts of bisphenol A epoxy resin, 70-80 parts of a curing agent, 1-2 parts of an accelerator and 5-8 parts of a filler; and the curing agent comprises an alicyclic anhydride curing agent, an alicyclic amine curing agent and a multi-sulfydryl organic ester compound. The above technical scheme solves the problem of insufficient strength of the light insulator in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of insulators, in particular to a high-strength lightweight insulator and a preparation method thereof. BACKGROUND

[0002] In the power system, epoxy resin composite insulators are widely used due to their insulation and lightweight advantages, but the problem of insufficient strength has long restricted the reliability of the power grid. The current low strength of such insulators is mainly due to the inherent defects of the epoxy resin and the curing agent system. The reason is that the commonly used curing agents include amine curing agents, anhydride curing agents, etc. Among them, the reaction speed of amine curing agent with epoxy resin is fast, and the low-temperature curing performance is excellent, but the cross-linked network formed by aliphatic amine curing agent and epoxy resin is mainly rigid amine bond, and the molecular chain segment movement ability is weak. The brittle glue layer formed after curing, when the insulator bears mechanical load, the stress cannot be dispersed through chain segment slip, and cracking is easily caused at defects, affecting the bending strength of the insulator. While anhydride curing agent has excellent insulation performance and aging resistance, but its activity is low, and the miscibility with epoxy resin is poor. In addition, the anhydride curing agent has a long curing time, and the thermosetting product formed after curing has high hardness, which is easily affected by external environmental temperature difference and cracking, seriously affecting the strength of the insulator.

[0003] Therefore, it is necessary to provide a high-strength lightweight insulator and a preparation method thereof. SUMMARY

[0004] The present application provides a high-strength lightweight insulator and a preparation method thereof, which solves the problem of insufficient strength of lightweight insulators in related technologies.

[0005] The technical scheme of the present application is as follows: the present application provides a high-strength lightweight insulator, which comprises a core rod and a fitting on both ends of the core rod. The outer surface of the core rod is injected with a shed sheath. The raw material of the core rod comprises glue and glass fiber. The glue comprises the following components by weight: bisphenol A epoxy resin 100 parts, curing agent 70-80 parts, accelerator 1-2 parts, and filler 5-8 parts. The curing agent comprises alicyclic anhydride curing agent, alicyclic amine curing agent and multi-thiol organic ester compound.

[0006] The addition of accelerator in the glue of the lightweight insulator can accelerate the ring-opening esterification reaction of anhydride, form hydrogen bond complex with alicyclic amine, adjust the reactivity of amine group, avoid local over-crosslinking, promote the formation of uniform and dense three-dimensional structure, and further improve the strength of the lightweight insulator.

[0007] As a further technical scheme, the alicyclic anhydride curing agent comprises one or more of tetrahydrophthalic anhydride, nadic anhydride and methyl nadic anhydride; preferably methyl nadic anhydride.

[0008] The curing agent in the compound of the light weight insulator of the present application comprises an alicyclic anhydride curing agent, the alicyclic anhydride curing agent contains a cyclic structure in the molecule, the miscibility of the alicyclic anhydride curing agent with the epoxy resin is significantly better than that of the traditional anhydride curing agent, and preferably, the alicyclic anhydride curing agent is methyl nadic anhydride, the methyl nadic anhydride is liquid and convenient to use, the contained norbornene double ring skeleton can form a highly regular three-dimensional crosslinking network after curing with the epoxy resin, and the steric hindrance effect of the double ring structure makes the crosslinking points more uniformly distributed in the matrix, which helps to improve the strength of the light weight insulator.

[0009] As a further technical solution, the alicyclic amine curing agent comprises one or more of isophorone diamine, menthane diamine and ortho-diamine cyclohexane, and preferably isophorone diamine.

[0010] The curing agent in the compound of the light weight insulator of the present application comprises an alicyclic amine curing agent, the amine group of the alicyclic amine curing agent is linked to an alicyclic ring, and due to the steric hindrance effect of the alicyclic ring, the reactivity of the active hydrogen is slightly lower than that of the aliphatic amine, the slower reaction speed allows the molecular chain to stretch more fully before crosslinking, and due to the presence of the alicyclic structure, the insulator can absorb energy by the deformation of the ring when being bent, avoiding brittle fracture caused by stress concentration, and further improving the strength of the light weight insulator.

[0011] As a further technical solution, the polythiol organic ester compound comprises one or more of dimercaptoacetic acid ethylene glycol ester, trimethylolpropane tri(3-mercaptopropionate) and pentaerythritol tetramercaptoacetate, and preferably trimethylolpropane tri(3-mercaptopropionate).

[0012] The curing agent in the compound of the light weight insulator of the present application comprises a polythiol organic ester compound, the polythiol organic ester compound contains a plurality of thiol active groups, and preferably, the polythiol organic ester compound is trimethylolpropane tri(3-mercaptopropionate), which contains a moderate number of thiol groups, when the number of thiol groups is too small, the active sites provided by the unit mass compound are insufficient, resulting in a slow curing reaction rate, and the un-crosslinked epoxy groups are prone to form linear molecular chain defects, and if the number of thiol groups is too large, the high thiol density will cause the curing reaction rate to be out of control, affecting the strength of the light weight insulator, therefore, the preferred trimethylolpropane tri(3-mercaptopropionate) can better improve the strength of the light weight 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] The mass ratio of the alicyclic anhydride curing agent, the alicyclic amine curing agent and the multi-sulfydryl organic ester compound in the rubber compound of the light-weight insulator is 5:2:1~1.5, wherein the alicyclic anhydride is used as the main curing agent, and the reaction of the alicyclic anhydride with the epoxy resin can form a regular network skeleton under the action of the accelerator; the addition amount of the alicyclic amine curing agent is moderate, the amino group in the alicyclic amine curing agent reacts with the epoxy group in the epoxy resin to introduce a polar amine bond into the crosslinked network, which can not only enhance the network density through hydrogen bonding, but also reduce the stress concentration points in the crosslinked network, so that the toughness of the initial skeleton is improved; and the addition amount of the multi-sulfydryl organic ester compound is the least, but it plays a key role in activity adjustment and performance optimization, the reaction rate of the whole curing system is controlled in a suitable range through the activity adjustment of the sulfydryl group, and the addition of the sulfydryl group can further alleviate the problem of large brittleness of the adhesive layer caused by the amine curing agent, and further improve the strength of the light-weight insulator.

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

[0016] As a further technical solution, the filler comprises the following components in parts by weight: 60~80 parts of aluminum oxide, 20~40 parts of silicon dioxide, and 8~10 parts of a mercaptobenzamide compound.

[0017] The filler in the rubber compound of the light-weight insulator comprises aluminum oxide, which has excellent dielectric insulation performance, stable crystal structure, can form a uniform insulation barrier in an electric field, effectively prevents charge migration, and improves the breakdown voltage threshold of the material; the dielectric performance of silicon dioxide matches well with the epoxy resin matrix, can fill the micro-pores 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 group in the epoxy resin, and the polar structure of the benzamide group can form a hydrogen bond with the hydroxyl group on the surface of aluminum oxide and silicon dioxide, thereby enhancing the interfacial bonding force between the filler and the resin matrix, reducing air gaps or defects at the interface, avoiding the concentration of electric field at the interface to cause breakdown, and enhancing the breakdown strength of the light-weight insulator.

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

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

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

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

[0022] As a further technical solution, the addition amount of the mercaptobenzamide compound is 8%-10% of the mass sum of alumina and silicon dioxide.

[0023] The application provides a preparation method of a high-strength light insulator.

[0024] S1, mixing raw materials of the glue to obtain a mixture A;

[0025] S2, introducing the glass fiber into a mold, injecting the mixture A, and curing after pultrusion molding to obtain a core rod;

[0026] S3, inserting a fitting on both ends of the core rod, and injecting an umbrella skirt sheath on the outer surface of the core rod to obtain a light insulator.

[0027] The working principle and beneficial effects of the application are as follows:

[0028] In the present application, the curing agent in the compound of the high-strength lightweight insulator adopts a compounding system of alicyclic anhydride curing agent, alicyclic amine curing agent and multi-thiol organic ester compound, thereby optimizing the crosslinking network and improving the strength of the insulator. In the prior art, the fatty amine curing agent of the epoxy resin has the problem of too high rigidity, and the activity of the anhydride curing agent is relatively low and the miscibility with the epoxy resin is relatively poor, which seriously affects the strength of the insulator. In the present application, the curing agent in the compound of the high-strength lightweight insulator adopts a compounding system of alicyclic anhydride curing agent, alicyclic amine curing agent and multi-thiol organic ester compound. The miscibility of the alicyclic anhydride curing agent with the epoxy resin is better, but the activity is poor. The presence of alicyclic in the alicyclic amine curing agent can not only limit the excessive slippage of the molecular chain through the ring structure, but also absorb external energy through the deformation of the ring twist, and the brittleness of the alicyclic amine curing agent is smaller than that of the conventional fatty amine curing agent, but the brittleness of the alicyclic amine curing agent used alone is still large. The multi-thiol organic ester compound has high reactivity of thiol groups, which can make up for the defect of poor activity of the alicyclic anhydride curing agent. The addition of active thiol groups helps to enhance the flexibility of the epoxy resin, further alleviates the problem of large brittleness of the amine curing agent glue layer, and the three are compounded to further optimize the crosslinking structure of the epoxy resin and improve the strength of the lightweight insulator. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0030] In the following examples and comparative examples:

[0031] Bisphenol A epoxy resin: model E51 (618);

[0032] Alumina: average particle size 30 nm;

[0033] Silicon dioxide: average particle size 50 nm.

[0034] Example 1

[0035] A preparation method of a high-strength lightweight insulator, comprising the following steps:

[0036] S1, mixing 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 a mixture A;

[0037] S2, introducing glass fiber into a mold, injecting the mixture A, and curing after pultrusion molding to obtain a core rod;

[0038] S3, inserting a gold fitting at both ends of the mandril, and injecting an umbrella skirt sheath on the outer surface of the mandril to obtain a lightweight insulator;

[0039] The curing agent is composed of methyl nadic anhydride, isophorone diamine and dimercapto glycol in a mass ratio of 5:2:1;

[0040] The filler includes: 60 parts of alumina and 40 parts of silica.

[0041] Example 2

[0042] A preparation method of a high-strength lightweight insulator, comprising the following steps:

[0043] S1, mixing 100 parts of bisphenol A epoxy resin, 75 parts of a curing agent, 1.5 parts of 2,4,6-tris (dimethylaminomethyl) phenol and 6 parts of a filler to obtain a mixture A;

[0044] S2, introducing glass fibers into a mold, injecting the mixture A, and curing after pultrusion molding to obtain a mandril;

[0045] S3, inserting a gold fitting at both ends of the mandril, and injecting an umbrella skirt sheath on the outer surface of the mandril to obtain a lightweight insulator;

[0046] The curing agent is composed of methyl nadic anhydride, isophorone diamine and dimercapto glycol in a mass ratio of 5:2:1;

[0047] The filler includes: 60 parts of alumina and 40 parts of silica.

[0048] Example 3

[0049] A preparation method of a high-strength lightweight insulator, comprising the following steps:

[0050] S1, mixing 100 parts of bisphenol A epoxy resin, 80 parts of a curing agent, 2 parts of 2,4,6-tris (dimethylaminomethyl) phenol and 8 parts of a filler to obtain a mixture A;

[0051] S2, introducing glass fibers into a mold, injecting the mixture A, and curing after pultrusion molding to obtain a mandril;

[0052] S3, inserting a gold fitting at both ends of the mandril, and injecting an umbrella skirt sheath on the outer surface of the mandril to obtain a lightweight insulator;

[0053] The curing agent is composed of methyl nadic anhydride, isophorone diamine and dimercapto glycol in a mass ratio of 5:2:1;

[0054] The filler includes: 60 parts of alumina and 40 parts of silica.

[0055] Example 4

[0056] Example 4 differs from Example 1 in that the curing agent consists of methylnadic anhydride, isophorone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 5:2:1.5.

[0057] Example 5

[0058] Example 5 differs from Example 4 in that the ethylene glycol dimercaptoacetate is replaced by an equivalent amount of trimethylolpropane tris(3-mercaptopropionate).

[0059] Example 6

[0060] Example 6 differs from Example 4 in that the ethylene glycol dimercaptoacetate is replaced by an equivalent amount of pentaerythritol tetramercaptoacetate.

[0061] Example 7

[0062] The preparation method of the filler comprises the following steps: dispersing 8 parts of 2-mercapto-N-methylbenzamide in 300 parts of anhydrous ethanol, adding 60 parts of alumina and 40 parts of silica, mixing for 3 h and then drying to obtain the filler;

[0063] Example 7 differs from Example 5 in that the filler is replaced by an equivalent amount of the filler obtained by the above preparation method.

[0064] Example 8

[0065] Example 8 differs from Example 7 in that the amount of 2-mercapto-N-methylbenzamide added is 10 parts.

[0066] Example 9

[0067] Example 9 differs from Example 7 in that the 2-mercapto-N-methylbenzamide is replaced by an equivalent amount of 3-mercapto-N-methyl-propionamide.

[0068] Comparative Example 1

[0069] Comparative Example 1 differs from Example 1 in that the curing agent consists of methylnadic anhydride and isophorone diamine in a mass ratio of 5:2.

[0070] Comparative Example 2

[0071] Comparative Example 2 differs from Example 1 in that the curing agent consists of methylnadic anhydride and ethylene glycol dimercaptoacetate in a mass ratio of 5:1.

[0072] Comparative Example 3

[0073] Comparative Example 3 differs from Example 1 in that the curing agent consists of isophorone diamine and ethylene glycol dimercaptoacetate in a mass ratio of 2:1.

[0074] Comparative Example 4

[0075] Comparative Example 4 differs from Example 1 in that the only curing agent is methyl nadic anhydride.

[0076] Comparative Example 5

[0077] Comparative Example 5 differs from Example 1 in that the only curing agent is isophorone diamine.

[0078] Experimental Example 1

[0079] The core rods in the high-strength lightweight insulators prepared from Examples 1-6 and Comparative Examples 1-5 were tested for bending strength according to the test method specified in DL / T 1580-2021 “Technical Conditions for Core Body of AC / DC Composite Insulator”, and the core rod diameter was 24 mm.

[0080] The test results are shown in Table 1.

[0081] Table 1: Performance test results of Examples 1-6 and Comparative Examples 1-5

[0082]

[0083] As can be seen from Table 1, when the curing agent includes alicyclic anhydride, alicyclic amine, and a multi-thiol organic ester compound, the bending strength of the insulator core rod can be improved.

[0084] Experimental Example 2

[0085] The core rods in the high-strength lightweight insulators prepared from Example 5 and Examples 7-9 were tested for breakdown strength according to the test method specified in DL / T 1580-2021 “Technical Conditions for Core Body of AC / DC Composite Insulator”.

[0086] The test results are shown in Table 2.

[0087] Table 2: Performance test results of Example 5 and Examples 7-9

[0088]

[0089] As can be seen from Table 2, when a thiol benzamide compound is added to the filler, the breakdown strength of the insulator core rod can be improved.

[0090] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high-strength, lightweight 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 an adhesive and glass fiber. The adhesive comprises the following components by weight: 100 parts bisphenol A epoxy resin, 70-80 parts curing agent, 1-2 parts accelerator, and 5-8 parts filler. The curing agent includes alicyclic anhydride curing agent, alicyclic amine curing agent, and polythiol organic ester compound. The alicyclic anhydride curing agent includes one or more of tetrahydrophthalic anhydride, nadikel anhydride, and methylnadikel anhydride. The alicyclic amine curing agent includes one or more of isophorone diamine, montanane diamine, and o-diaminocyclohexane; The polythiol organic ester compounds include one or more of ethylene glycol dithioglycolate, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrathioglycolate. 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.

2. The high-strength lightweight 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.

3. The high-strength lightweight 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.

4. A high-strength lightweight insulator according to claim 3, 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.

5. A high-strength lightweight insulator according to claim 3, 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.

6. A method for preparing a high-strength lightweight insulator, used to prepare the high-strength lightweight insulator according to any one of claims 1 to 5, 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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