CN116003968A - A preparation method for a rigid umbrella skirt applied to a composite cross-arm - Google Patents

Abstract

The invention discloses a method for preparing a rigid shed applied to a composite cross arm. Bisphenol A type epoxy resin, dimer acid modified epoxy resin, curing agent and accelerator are used as raw materials to prepare an electrical The hard umbrella skirt with excellent characteristics and mechanical properties, the hard umbrella skirt made by the present invention is applied to the composite cross-arm, after testing, the hard umbrella skirt of the present invention can solve the problem of the traditional composite cross-arm umbrella skirt due to human trampling, Losses from issues such as bird pecks and damage from strong winds.

Description

A preparation method for a rigid umbrella skirt applied to a composite cross-arm

technical field

The invention relates to the field of composite insulating cross-arms, in particular to a preparation method for a rigid shed applied to composite cross-arms.

Background technique

The composite insulating cross-arm tower is composed of a steel structure tower body and a composite insulating cross-arm, which is replacing the combination of "iron cross-arm + side-phase insulator" of the traditional line. The composite material of the composite insulation cross arm is one of the ideal materials for building power towers due to its advantages of light weight, high strength, corrosion resistance, easy processing, designability and good insulation performance. Composite insulation cross-arm can give full play to its superior insulation performance, realize the perfect combination of functional materials and structural materials, and maximize the performance of composite materials, which has significant technical advantages and application prospects.

Dimer acid modified epoxy resin is an adduct of epichlorohydrin and dibasic fatty acid, which has good adhesion, excellent resistance to external impact and thermal shock, good lap shear strength and resistance creep properties etc. Among them, EPD-172 dimer acid modified epoxy resin is a combination of C18-unsaturated fatty acid dimer and 4,4'-(1-methylethylene) bi(di)phenol and chloromethyl oxirane Polymers, usually mixed with other epoxy resins and diluents, are used in the electrical materials industry to toughen epoxy systems, improve adhesion and peel strength. EPD-172 epoxy resin can effectively improve the mechanical shock resistance of the cured product and increase the service life of electrical equipment. However, it has disadvantages such as low yield and high price.

The bisphenol A type epoxy resin has convenient source of raw materials and low cost, and is the most widely used in epoxy resin, and its output accounts for more than 85% of the total output of epoxy resin. E-51 type bisphenol A epoxy resin has excellent insulation performance and corrosion resistance, but its heat resistance and weather resistance are poor, and its toughness is not good. Therefore, by blending EPD-172 dimer acid modified epoxy resin and E-51 type bisphenol A epoxy resin, the advantages of both can be combined to obtain a new type of epoxy resin with excellent comprehensive performance.

The application number is CN106567604A, a shed skirt type cement-based composite insulating cross-arm and its preparation process. In this method, materials such as short fibers, water-based epoxy resin, Portland cement and quartz sand are mixed and stirred into cement-based composite materials, which are cured at high temperature. Finally, a composite insulating part with a shed structure is formed. Although the mechanical strength has been improved somewhat, the composite material is heavy and has poor crack resistance.

The application number is CN113845757A, a corrosion-resistant high-electric performance resin and its preparation method. The corrosion-resistant high-electric performance resin is composed of epoxy resin, curing agent and accelerator, and the epoxy resin is composed of 3,4-epoxycyclohexyl Methyl 3,4-epoxycyclohexyl carboxylate and bisphenol A type epoxy resin, the 3,4-epoxycyclohexyl methyl 3,4-epoxy cyclohexyl carboxylate consumption accounts for the 10% to 40% of the mass of epoxy resin. With the improvement of composite material technology and production process, silicone rubber cross arm is widely used in China at present, that is, silicone rubber shed and sheath are set on the composite material mandrel, which has good pollution flashover characteristics. However, in practical applications, it was found that the silicone rubber insulating cross-arm has the disadvantages of low mechanical strength and cannot be stepped on by humans, and the silicone rubber umbrella skirt and sheath are more seriously damaged by birds and strong winds. In view of the fact that Hainan is an island city with hot and humid weather More, it is easy to cause aging and cracking of the umbrella skirt, and the service life is reduced. Therefore, choosing a more reasonable insulating material and improving the shed of the composite cross arm into a hard shed with better mechanical strength can effectively improve the safety and reliability of the power line and reduce the loss of the hard shed.

Contents of the invention

In view of this, the present invention proposes a method for preparing a rigid shed applied to a composite cross arm to solve the above problems.

Technical scheme of the present invention is realized like this:

A rigid umbrella skirt applied to a composite cross arm, comprising bisphenol A epoxy resin and dimer acid modified epoxy resin, wherein the dimer acid modified epoxy resin is EPD-172 epoxy resin.

Further, in parts by weight, the dimer acid modified epoxy resin is 9-11 parts, the bisphenol A epoxy resin is 88-92 parts, the curing agent is 68-72 parts, and the accelerator is 0.49-0.53 parts.

Further, the bisphenol A epoxy resin is E-51 type bisphenol A epoxy resin, the curing agent is 2-methylhexahydrophthalic anhydride, and the accelerator is 2,4,6-tri( Dimethylaminomethyl)phenol.

Further, it is characterized in that it comprises the following steps:

(1) adding bisphenol A epoxy resin and dimer acid modified epoxy resin to the container and mixing, then adding curing agent and accelerator successively, mixing in a water bath to obtain resin glue;

(2) Put the resin glue solution into a vacuum oven for processing to obtain epoxy resin glue;

(3) Pour the epoxy resin compound into the mold, vacuum defoaming treatment, solidification, cooling, and demoulding to obtain the finished product.

Further, in step (1), the temperature of the water bath is 55-65° C., and the mixture is stirred in the water bath for 6-8 minutes.

Further, in step (2), the temperature of the vacuum drying oven is 55-65° C., and the drying time is 13-17 minutes.

Further, in step (3), the vacuum defoaming treatment temperature is 55-65° C., and the drying time is 13-17 minutes.

Further, in step (3), the curing temperature is 130-150° C., and the curing time is 9-11 hours.

Further, the preparation method of the composite insulating cross-arm with a hard shed: first, connect the two ends of the insulating mandrel to the fittings, and obtain the composite of the insulating mandrel and the fittings by crimping; secondly, compound the insulating mandrel and the fittings After the body is preheated, put it into the mold, close the mold, and then inject the vacuum-stirred mixed epoxy resin until the glue entering the mold is filled; finally, put the mold and the product into the heating and curing furnace for curing , curing the mixed epoxy resin compound used as the outer insulating shed, and obtaining a composite insulating cross-arm with a hard shed after curing.

Compared with prior art, the beneficial effect of the present invention is:

In the present invention, prepare a kind of rigid shed that is applied to composite insulation cross arm, is made up of bisphenol A type epoxy resin and dimer acid modified epoxy resin, and concrete dimer acid modified epoxy resin is EPD- 172 epoxy resin. The hard shed prepared by the invention has the advantages of lightness, good crack resistance, etc., and its electrical and mechanical properties are improved. The results of the mechanical performance test show that the rigid umbrella shed prepared by the invention has excellent mechanical performance and can be used in strong wind climates and strong bird pecking conditions. After damp heat resistance and salt spray aging test, after 96h of damp heat aging and 21d of salt spray aging, the leakage current after 96h of damp heat aging is 37.60μA, the breakdown field strength is 36.68kV/mm, the bending strength is 16.88MPa, and the tensile strength is 16.88MPa. is 61.15MPa; after salt spray aging for 21 days, the leakage current is 36.35μA, the breakdown field strength is 38.6kV/mm, the bending strength is 22.56MPa, and the tensile strength is 60.42MPa. The results show that the hard shed shed made by the present invention Excellent aging resistance, able to adapt to the local weather and prolong the service life of the hard shed.

Description of drawings

Fig. 1 is the composite cross-arm schematic diagram of the present invention, hard umbrella skirt 2, hard sheath 3, mandrel and fittings 1, hard sheath is wrapped in the outside of mandrel, on the outer surface of hard sheath, set A plurality of hard umbrella skirts, the umbrella skirt adopts the hard umbrella skirt prepared by the present invention, the metal fittings are arranged at both ends of the mandrel, and the mandrel is located in the central hole of the metal fitting.

Detailed ways

In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

Example 1

Step 1, in parts by weight, weigh 90 parts of E-51 resin and 10 parts of dimer acid modified epoxy resin EPD-172 resin, add them to the container, and then weigh 70 parts of curing agent 2-methylhexahydrophthalic anhydride Parts, added to the container, and finally 0.51 parts of accelerator (DMP-30) were added;

Step 2, keep a constant temperature of 60°C in a water bath and stir for 7 minutes to prepare resin glue;

Step 3: Carry out vacuum defoaming treatment for 15 minutes in a vacuum drying oven with a temperature environment of 60° C. to obtain a vacuum-stirred epoxy resin compound;

Step 4, slowly pour the mixed solution into a preheated stainless steel mold coated with a release agent, and then conduct constant temperature and vacuum defoaming treatment for 15 minutes;

Step 5: Curing at a temperature of 140°C for 10 hours, cooling naturally, and demolding to obtain a cured product of EPD-172/E-51 blend resin, and testing the relevant characteristics of the hard shed material.

The preparation method of the composite insulating cross-arm with a hard shed: first, connect the two ends of the insulating mandrel to the fittings, and obtain the insulating mandrel and the fittings complex by crimping; secondly, preheat the insulating mandrel and the fittings complex Finally, put it into the mold, close the mold, and then inject the mixed epoxy resin compound that has been stirred in vacuum until the compound that enters the mold is filled; finally, put the mold and the product into the heating and curing furnace for curing. The mixed epoxy resin compound of the outer insulating shed is cured, and a composite insulating cross arm with a hard shed is obtained after curing.

Example 2

Step 1, in parts by weight, weigh 88 parts of E-51 resin and 9 parts of dimer acid modified epoxy resin EPD-172 resin, add them to the container, and then weigh 68 parts of curing agent 2-methylhexahydrophthalic anhydride Parts, added to the container, and finally 0.49 parts of accelerator (DMP-30) were added;

Step 2, keep stirring in a water bath at a constant temperature of 55°C for 6 minutes to prepare resin glue;

Step 3: Carry out vacuum defoaming treatment for 15 minutes in a vacuum drying oven with a temperature environment of 55° C. to obtain a vacuum-stirred epoxy resin compound;

Step 4, slowly pour the mixed solution into a preheated stainless steel mold coated with a release agent, and then conduct constant temperature and vacuum defoaming treatment for 15 minutes, the temperature being 55°C;

Step 5: Curing at a temperature of 130°C for 9 hours, cooling naturally, and demolding to obtain a cured product of EPD-172/E-51 blend resin, and testing the relevant characteristics of the hard shed material.

The preparation method of the composite insulating cross-arm with a hard shed: first, connect the two ends of the insulating mandrel to the fittings, and obtain the insulating mandrel and the fittings complex by crimping; secondly, preheat the insulating mandrel and the fittings complex Finally, put it into the mold, close the mold, and then inject the mixed epoxy resin compound that has been stirred in vacuum until the compound that enters the mold is filled; finally, put the mold and the product into the heating and curing furnace for curing. The mixed epoxy resin compound of the outer insulating shed is cured, and after curing, a composite insulating cross arm with a hard shed is obtained

Example 3

Step 1, in parts by weight, weigh 92 parts of E-51 resin and 11 parts of dimer acid modified epoxy resin EPD-172 resin, add them to the container, and then weigh 72 parts of curing agent 2-methylhexahydrophthalic anhydride Parts, added to the container, and finally 0.53 parts of accelerator (DMP-30) were added;

Step 2, keep stirring in a water bath at a constant temperature of 65°C for 8 minutes to prepare resin glue;

Step 3: Carry out vacuum defoaming treatment for 15 minutes in a vacuum drying oven with a temperature environment of 65° C. to obtain a vacuum-stirred epoxy resin compound;

Step 4: Slowly pour the mixed solution into a preheated stainless steel mold coated with a release agent, and then conduct constant temperature and vacuum defoaming treatment for 15 minutes at a temperature of 65°C;

Step 5: Curing at a temperature of 150°C for 11 hours, cooling naturally, and demoulding to obtain a cured EPD-172/E-51 blend resin, and testing the relevant characteristics of the hard shed material.

The preparation method of the composite insulating cross-arm with a hard shed: first, connect the two ends of the insulating mandrel to the fittings, and obtain the insulating mandrel and the fittings complex by crimping; secondly, preheat the insulating mandrel and the fittings complex Finally, put it into the mold, close the mold, and then inject the mixed epoxy resin compound that has been stirred in vacuum until the compound that enters the mold is filled; finally, put the mold and the product into the heating and curing furnace for curing. The mixed epoxy resin compound of the outer insulating shed is cured, and a composite insulating cross arm with a hard shed is obtained after curing.

Test example 1

The following methods are used to detect the performance of the hard shed made in Example 1.

1. Humidity and heat aging resistance performance test: The artificial accelerated aging test is carried out on the prepared hard shed sample by using an 85°C deionized water bath. The sampling period is 4d, 8d, 12d, 16d. The mechanical and electrical properties of the shed samples before and after aging were measured.

2. Salt spray aging resistance test: According to the standard GB/T 2423.17-2008, the aging test is carried out on the prepared hard shed sample. Using neutral salt spray conditions, the test solution is an aqueous solution of analytically pure NaCl with a mass fraction of 5%. Keep the sample in a constant temperature environment of 35°C and the relative humidity at the nozzle is at least 85%. The sampling period is 4d, 7d, 14d, 28d. After sampling, the surface of the sample was cleaned with deionized water to remove the influence of mist. The mechanical and electrical properties of the shed samples before and after aging were measured.

3. Mechanical performance test: test the prepared hard shed sample according to the standard ISO527-2. The central width of the dumbbell-shaped tensile sample cut by an engraving machine is 10mm, the gauge length is 50mm, and the test speed is 5mm/min. In the bending test, according to the standard IS178, the size of the cuboid sample cut by engraving machine is 80×15×4mm, the span is 64mm, and the test speed is 2mm/min.

4. Leakage current test: Test the prepared hard shed samples according to the standard DL/T 1580-2016. The length of the test product is 300mm±0.5mm, and the leakage current value under the power frequency 12kV voltage is measured with an oscilloscope.

5. Power frequency breakdown test: test the prepared hard shed samples according to the standard IEC 60243-1-2013. Place a square test piece with a side length of 150mm and a thickness of 1mm in a transparent glass container filled with simethicone oil to ensure that the silicone oil is covered by 5-7mm of the sample. Select 3 test pieces for each group of samples, and take 5 breakdown test points for each test piece.

6. Dielectric loss test: Use a dielectric loss measuring instrument to test the dielectric loss factor of the test sample at room temperature at 50 Hz. The dielectric loss sample is a circular sheet sample with a side length of 30mm and a thickness of 3mm.

The bending strength and tensile strength of the hard shed made in Example 1 of the present invention are 23.01MPa and 82.72MPa respectively. The experimental results show that the mechanical properties of the hard shed are excellent, which can meet the requirements of strong wind and strong bird pecking. application.

The leakage current of the rigid shed manufactured in Example 1 of the present invention before aging is 35.42μA, the breakdown field strength is 43.8kV/mm, the bending strength is 23.01MPa, and the tensile strength is 82.72MPa. After 96 hours of damp heat aging and 21 days of salt spray aging, the leakage current of 96 hours of damp heat aging is 37.60μA, the breakdown field strength is 36.68kV/mm, the bending strength is 16.88MPa, and the tensile strength is 61.15MPa; the leakage current of 21d salt spray aging is 36.35μA, the breakdown field strength is 38.6kV/mm, the bending strength is 22.56MPa, and the tensile strength is 60.42MPa. Experimental results show that the hard shed prepared by the invention has good resistance to damp heat aging and salt spray, can adapt to the weather in Hainan Province, and reduce material loss caused by environmental factors.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (7)

1. The hard umbrella skirt is characterized by comprising 9-11 parts of dimer acid modified epoxy resin, 88-92 parts of bisphenol A epoxy resin, 68-72 parts of curing agent and 0.49-0.53 part of accelerator in parts by weight.

2. The hard umbrella skirt for composite cross arms of claim 1, wherein the bisphenol a epoxy resin is E-51 bisphenol a epoxy resin, the curing agent is 2-methyl hexahydrophthalic anhydride, and the accelerator is 2,4, 6-tris (dimethylaminomethyl) phenol.

3. The method for manufacturing a hard umbrella skirt applied to a composite cross arm according to claim 1, comprising the following steps:

(1) Adding bisphenol A epoxy resin and dimer acid modified epoxy resin into a container for mixing, sequentially adding a curing agent and an accelerator, and mixing in a water bath to obtain resin glue solution;

(2) Placing the resin glue solution into a vacuum drying oven for treatment to obtain epoxy resin glue;

(3) Pouring the epoxy resin sizing material into a mould, carrying out vacuum defoaming treatment, solidifying, cooling and demoulding to obtain a finished product.

4. The method for preparing the hard umbrella skirt applied to the composite cross arm according to claim 3, wherein in the step (1), the temperature of the water bath kettle is 55-65 ℃, and the mixture is stirred in the water bath kettle for 6-8min.

5. A method for producing a hard umbrella skirt for a composite cross arm according to claim 3, wherein in the step (2), the temperature of the vacuum drying oven is 55-65 ℃ and the drying time is 13-17min.

6. A method for producing a hard umbrella skirt for a composite cross arm according to claim 3, wherein in the step (3), the vacuum defoaming treatment temperature is 55-65 ℃ and the drying time is 13-17min.

7. The method for producing a rigid umbrella skirt for a composite cross arm according to claim 4, wherein in the step (3), the curing temperature is 130-150 ℃ and the curing time is 9-11h.

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