CN110845823A - Benzoxazine modified epoxy resin insulating material, epoxy casting insulating part and preparation method thereof - Google Patents
Benzoxazine modified epoxy resin insulating material, epoxy casting insulating part and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a benzoxazine modified epoxy resin insulating material, an epoxy casting insulating part and a preparation method thereof, wherein the insulating material is prepared from a mixture of bisphenol A benzoxazine resin and epoxy resin, and the mass ratio of the bisphenol A benzoxazine resin to the epoxy resin mixture is 1 (4.7-4.96); the epoxy resin mixture consists of bisphenol A epoxy resin, an aliphatic anhydride curing agent and an alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the aliphatic anhydride curing agent to the alumina filler is 1 (0.50-0.56) to 3.2-3.4. The insulating material has high mechanical strength and breakdown strength, the thermoelectric aging time of the insulator exceeds 1000h, and the insulating material is suitable for occasions with high mechanical load and insulating property requirements, greatly improves the reliability of the supporting epoxy cast insulator for the high-voltage switch, and meets the requirement of insulator size miniaturization.
Description
Technical Field
The invention belongs to the technical field of high-molecular insulating materials, and particularly relates to a benzoxazine modified epoxy resin insulating material, an epoxy casting insulating part and a preparation method thereof.
Background
Epoxy cast insulators such as insulating cylinders and post insulators for high-voltage switchgear are used in the high-voltage switchgear, play a role in supporting and insulating, and have high requirements on mechanical strength (especially bending strength) and insulating performance (especially breakdown strength). Under the development trend of miniaturization of the high-voltage switch at present, the volume of the insulator is required to be continuously reduced, so that the epoxy cast insulator is manufactured by adopting an insulating material with high mechanical strength and high insulating property, the reliability of the high-voltage switch equipment is improved, and the epoxy cast insulator is an important direction for the development of the support insulator at present.
For example, in the prior art, chinese patent No. CN103709608B discloses an outdoor mutual-induction electrical insulation epoxy resin castable, which is composed of the following materials (by weight ratio): 21-26% of resin, 45-55% of filler, 15-25% of curing agent and 2-6% of other auxiliary agents; the resin is formed by mixing organic silicon modified epoxy resin, phenolic epoxy resin, brominated epoxy resin and bisphenol F epoxy resin; according to the weight ratio, the organic silicon modified epoxy resin accounts for 20 percent, the novolac epoxy resin accounts for 20 percent, the brominated epoxy resin accounts for 10 percent, and the bisphenol F type epoxy resin accounts for 50 percent; the filler is silane-treated silicon micropowder; the curing agent is modified methylhexahydrophthalic anhydride; other auxiliary agents comprise methylimidazole curing accelerator, plasticizer, reactive diluent, silane coupling agent, coloring agent and antioxidant. The castable has excellent physical and chemical properties, and has the properties of heat resistance, low temperature resistance, ultraviolet irradiation resistance, ageing resistance and the like.
However, due to the limitation of epoxy resin, the bending strength of the current advanced insulating materials such as N2S series formula adopted by Toshiba japonica is generally not more than 140MPa, and the alternating current breakdown strength is not more than 33kV/mm, so that the miniaturization degree of the supporting insulator is limited; the mechanical property and the insulating property of the existing epoxy resin castable can not meet the requirement of the size miniaturization of the insulator.
Disclosure of Invention
The invention aims to provide a benzoxazine modified epoxy resin insulating material which has high mechanical strength and breakdown strength and meets the requirement of volume miniaturization of insulating parts.
Another object of the present invention is to provide an epoxy-cast insulating member using the above insulating material and a method for preparing the same.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a benzoxazine modified epoxy resin insulation material is prepared from a mixture of bisphenol A benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol A benzoxazine resin to the epoxy resin mixture is 1 (4.7-4.96); the epoxy resin mixture consists of bisphenol A epoxy resin, an aliphatic anhydride curing agent and an alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the aliphatic anhydride curing agent to the alumina filler is 1 (0.50-0.56) to 3.2-3.4.
The bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1 (2.5-3.5) to 5.5-6.5;
wherein, the component one is benzoxazine KB 4170;
the component two is any one or combination of benzoxazine KB6100 and KB 6600;
the component III is any one or combination of benzoxazine KB7165, KB7170, KB7200, KB7280 and KB 7290.
And mixing the first component, the second component and the third component in proportion to prepare the bisphenol A type benzoxazine resin for later use.
The benzoxazines KB4170, KB6100, KB6600, KB7165, KB7170, KB7200, KB7280 and KB7290 are all produced by Zibocolol macromolecular materials Co. The bisphenol A benzoxazine resin is liquid resin.
The bisphenol A type epoxy resin is CY5995 and EPIKOTETMAny one or combination of Resin 805, CT 200M. The bisphenol A type epoxy resin used is a solid resin.
The aliphatic anhydride curing agent is methyl tetrahydrophthalic anhydride. The methyl tetrahydrophthalic anhydride curing agent is in a liquid state, the viscosity is only 500 mPa.s, and the curing rate of the curing agent is relatively slow, so that a cured product with a compact molecular structure can be formed.
The alumina filler is electrician α -Al2O3. Preferably, the alumina filler is any one or a mixture of types A-F-3, A-F-4 and A-F-5 of Zhengzhou light metal research institute in the aluminum industry of China in any proportion.
The benzoxazine modified epoxy resin insulating material is prepared from a mixture of bisphenol A benzoxazine resin and epoxy resin, utilizes the characteristics of high mechanical strength, excellent heat resistance and excellent insulating property of the bisphenol A benzoxazine resin, combines the characteristics of good heat resistance and excellent insulating property of the bisphenol A epoxy resin, obtains the insulating material simultaneously having high mechanical strength and high insulating property through copolymerization modification of the benzoxazine resin and the epoxy resin, and solves the problem that the mechanical strength and the electrical insulating property of an epoxy cast insulator are difficult to take into account; the epoxy cast insulator made of the insulating material has the advantages that the service life of the supporting type insulator for the high-voltage switch is prolonged, the thermoelectric aging time of the insulator exceeds 1000h, the epoxy cast insulator is suitable for occasions with high mechanical load and insulating property requirements, the reliability of the supporting type epoxy cast insulator for the high-voltage switch is greatly improved, and the requirement of the miniaturization of the volume of the insulator is met.
The epoxy casting insulating component is made of the benzoxazine modified epoxy resin insulating material.
The epoxy casting insulating part adopts the benzoxazine modified epoxy resin insulating material, and is used in a position of a high-voltage switch which has higher mechanical load requirements and insulating property requirements, so that the reliability of the insulator is greatly improved, the service life of the insulator is greatly prolonged, and the maintenance and overhaul cost of a power station is reduced.
The preparation method of the epoxy casting insulating part comprises the following steps:
1) preheating bisphenol A epoxy resin, mixing with an alumina filler at 125-135 ℃, and degassing to obtain a mixture A;
2) mixing the mixture A with preheated bisphenol A type benzoxazine resin, and reacting at 125-135 ℃ to obtain a mixture B;
3) and mixing the mixture B with the preheated aliphatic anhydride curing agent, pouring the mixture B into a preheated mold under the conditions of 125-135 ℃ and 2-5 mbar of vacuum degree, standing, curing and stress-relieving treatment.
In the step 1), the preheating temperature of the bisphenol A type epoxy resin is 120-130 ℃, and the preheating time is 0.5-1.5 h; in the step 2), preheating the bisphenol A benzoxazine resin at a preheating temperature of 55-65 ℃ for 0.5h under a vacuum degree of 2-5 mbar; in the step 3), the aliphatic anhydride curing agent is preheated under the condition that the vacuum degree is 2-5 mbar, the preheating temperature is 55-65 ℃, and the preheating time is 0.5 h.
In the step 1), the degassing treatment is heat preservation and pressure maintaining for 1.0-2.0 h at 125-135 ℃ and under the condition that the vacuum degree is 4-7 mbar. The viscosity of the mixture A obtained in step 1) is not more than 7000 mPas.
In the step 2), the reaction time is 0.5 h. The viscosity of the mixture B obtained in step 2) is not more than 7000 mPas.
In the step 3), the preheating temperature of the die is 120-130 ℃, and the preheating time is 1.5-2.5 h. In the step 3), the viscosity of the casting material is not more than 5000mPa & s during casting.
And in the step 3), standing for 5-15 min under the condition of heat preservation and pressure maintaining.
In the step 3), the curing adopts a three-stage curing process: and (3) preserving heat for 5.5-6.5 h at 110-120 ℃ for the first-stage curing, then heating to 120-130 ℃ and preserving heat for 3.5-4.5 h for the second-stage curing, then heating to 130-140 ℃ and preserving heat for 1.5-2.5 h for the third-stage curing, then cooling to room temperature along with the furnace, and demolding.
The three-stage curing process is adopted to obtain the cured product, the time lasts for a long time, and the fully crosslinked blending modified cured product is convenient to form. Wherein, the first stage solidification is a gelling process, so that the mixture gels and forms a semi-solid tissue; the second stage of solidification is a primary cross-linking and interpenetrating process, wherein the semi-solid tissue starts to cross-link and interpenetrate, and has a net structure initially to form a solid tissue; the third stage of curing is a continuous cross-linking and interpenetrating process, and the solid tissues are further cross-linked and interpenetrating to form a network macromolecular body structure.
In the step 3), the stress relief treatment refers to heat preservation for 1.5-2.5 hours at 130-140 ℃ under the condition of no external force. And the internal stress of the cured material is reduced by constant-temperature stress relief treatment.
According to the preparation method of the epoxy casting insulation part, a vacuum casting process is adopted, parameters such as temperature, vacuum degree and time are adjusted according to the characteristics of bisphenol A epoxy resin and bisphenol A benzoxazine resin, and a static mixing technology is used for casting; the preparation method comprises the steps of premixing the bisphenol A epoxy resin and the alumina filler, adding the mixed solution of the bisphenol A benzoxazine resin formula, carrying out a preliminary reaction through co-heating mixing, and carrying out a continuous copolymerization reaction in the vacuum pouring and curing stage after the aliphatic anhydride curing agent is added.
According to the preparation method of the epoxy casting insulating part, the glass transition temperature of the obtained epoxy casting insulating part is equivalent to that of the traditional material, the bending strength and the electrical strength are higher, the performance in a thermoelectric aging test is better, the epoxy casting insulating part is suitable for a position of a high-voltage switch which has higher mechanical load requirements and insulating performance requirements, the reliability of the insulator is greatly improved, the service life of the insulator is greatly prolonged, and the maintenance and overhaul cost of a power station is reduced.
Drawings
FIG. 1 is a schematic view of a structure of an insulator for detecting thermal electrical aging in an experimental example;
FIG. 2 is a schematic view of load loading for detecting thermoelectric aging in an experimental example;
in the figure, 1-an insulator body, 2-a metal insert, 3-a fixing device and 4-a connecting block.
Detailed Description
The present invention will be further described with reference to the following embodiments.
In a specific embodiment, the bisphenol a benzoxazine resins KB4170, KB6100, KB6600, KB7165, KB7170, KB7200, KB7280 and KB7290 are all produced by zibocolol polymer materials ltd.
Bisphenol A epoxy resin CY5995 available from HUNTSMAN, EPIKOTETMResin 805 is available from HEXION Inc., and CT200M is available from Rice-Rice Fine chemical (Wuxi) Inc.
The A-F-3 type, A-F-4 type and A-F-5 type alumina fillers are provided by Zhengzhou light metal research institute of aluminum industry in China.
In a specific embodiment, the casting is carried out using a static mixing technique using an epoxy vacuum casting system manufactured by Asahi Baishi, Germany.
Example 1
The benzoxazine modified epoxy resin insulating material of the embodiment is prepared from a mixture of bisphenol a benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol a benzoxazine resin to the epoxy resin mixture is 1: 4.7; the epoxy resin mixture is composed of bisphenol A epoxy resin, a curing agent methyltetrahydrophthalic anhydride and an A-F-3 type alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the curing agent methyltetrahydrophthalic anhydride to the A-F-3 type alumina filler is 1:0.50: 3.2. The bisphenol A type epoxy resin is CY 5995.
The bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1:2.5: 6.5; wherein, the component one is benzoxazine KB 4170; component two is benzoxazine KB 6100; and the component III is benzoxazine KB 7165. And mixing the first component, the second component and the third component in proportion to prepare the bisphenol A type benzoxazine resin for later use.
The epoxy casting insulating part of the embodiment is made of the benzoxazine modified epoxy resin insulating material, and the preparation method comprises the following steps:
1) preheating bisphenol A type epoxy resin with the formula amount at 125 ℃ for 1h, mixing the bisphenol A type epoxy resin with alumina filler at 130 ℃ for 0.5h, and carrying out degassing treatment under the conditions of 130 ℃ and 5mbar vacuum degree for 1.5h under heat preservation and pressure preservation to obtain a mixture A; the viscosity of the mixture A is not more than 7000 mPas;
2) preheating bisphenol A type benzoxazine resin for 0.5h at the temperature of 60 ℃ and the vacuum degree of 4 mbar;
mixing the mixture A with preheated bisphenol A type benzoxazine resin, and carrying out primary reaction for 0.5h at the temperature of 130 ℃ and the vacuum degree of 4mbar to obtain a mixture B; the viscosity of the mixture B is not more than 7000 mPas;
3) preheating curing agent methyl tetrahydrophthalic anhydride for 0.5h at 60 ℃ under the condition of vacuum degree of 4 mbar; preheating the mould at 125 ℃ for 2 h;
mixing the mixture B with preheated curing agent methyl tetrahydrophthalic anhydride, pouring (static mixing type pouring) into a preheated mold under the conditions of 130 ℃ and 4mbar of vacuum degree, keeping the temperature and pressure in an equipment pouring tank, standing for 10min, and conveying the mold from the pouring tank to a curing furnace for curing;
the curing adopts a three-stage curing process: keeping the temperature at 115 ℃ for 6h for first-stage curing, then heating to 125 ℃ and keeping the temperature for 4h for second-stage curing, then heating to 135 ℃ and keeping the temperature for 2h for third-stage curing, then closing a heating and blowing system of a curing furnace, not opening a furnace door, cooling to room temperature along with the furnace, demolding and finishing;
then constant temperature stress relief treatment is carried out: and (3) preserving the heat for 2.0 hours at 135 ℃ under the condition of not applying external force to obtain the epoxy casting insulating part.
Example 2
The benzoxazine modified epoxy resin insulating material of the embodiment is prepared from a mixture of bisphenol a benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol a benzoxazine resin to the epoxy resin mixture is 1: 4.96; the epoxy resin mixture is composed of bisphenol A epoxy resin, a curing agent methyltetrahydrophthalic anhydride and an A-F-4 type alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the curing agent methyltetrahydrophthalic anhydride to the A-F-4 type alumina filler is 1:0.56: 3.4. The bisphenol A type epoxy resin is EPIKOTETMResin 805。
The bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1:2.5: 6.5; wherein, the component one is benzoxazine KB 4170; the component two is a mixture of benzoxazine KB6100 and KB6600 in a mass ratio of 1: 1; and the component III is benzoxazine KB 7170. And mixing the first component, the second component and the third component in proportion to prepare the bisphenol A type benzoxazine resin for later use.
The epoxy casting insulating part of the embodiment is made of the benzoxazine modified epoxy resin insulating material, and the preparation method comprises the following steps:
1) preheating bisphenol A type epoxy resin with the formula amount at 120 ℃ for 1.5h, mixing the bisphenol A type epoxy resin with alumina filler at 125 ℃ for 0.5h, and carrying out degassing treatment under the conditions of 125 ℃ and a vacuum degree of 4mbar for 2.0h under heat preservation and pressure preservation to obtain a mixture A; the viscosity of the mixture A is not more than 7000 mPas;
2) preheating bisphenol A type benzoxazine resin for 0.5h at the temperature of 55 ℃ and the vacuum degree of 2 mbar;
mixing the mixture A with preheated bisphenol A type benzoxazine resin, and carrying out primary reaction for 0.5h at 125 ℃ and under the vacuum degree of 5mbar to obtain a mixture B; the viscosity of the mixture B is not more than 7000 mPas;
3) preheating curing agent methyl tetrahydrophthalic anhydride for 0.5h at 55 ℃ and under the condition of vacuum degree of 2 mbar; preheating the mould at 120 ℃ for 2.5 h;
mixing the mixture B with preheated curing agent methyl tetrahydrophthalic anhydride, pouring (static mixing type pouring) into a preheated mold under the conditions of 125 ℃ and 2mbar vacuum degree, keeping the temperature and pressure in an equipment pouring tank, standing for 15min, and then conveying the mold from the pouring tank to a curing furnace for curing;
the curing adopts a three-stage curing process: preserving heat at 120 ℃ for 5.5h for first-stage curing, then heating to 130 ℃ and preserving heat for 3.5h for second-stage curing, then heating to 140 ℃ and preserving heat for 1.5h for third-stage curing, then closing a heating and blowing system of a curing oven, cooling to room temperature along with the oven without opening an oven door, demolding and finishing;
then constant temperature stress relief treatment is carried out: and (3) preserving the heat for 1.5 hours at 140 ℃ under the condition of not applying external force to obtain the epoxy casting insulating part.
Example 3
The benzoxazine modified epoxy resin insulating material of the embodiment is prepared from a mixture of bisphenol a benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol a benzoxazine resin to the epoxy resin mixture is 1: 4.85; the epoxy resin mixture is composed of bisphenol A epoxy resin, a curing agent methyltetrahydrophthalic anhydride and an A-F-5 type alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the curing agent methyltetrahydrophthalic anhydride to the A-F-5 type alumina filler is 1:0.52: 3.3. The bisphenol A epoxy resin is CT 200M.
The bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1:2.5: 6.5; wherein, the component one is benzoxazine KB 4170; the component two is benzoxazine KB 6600; the component III is a mixture of benzoxazine KB7200, KB7280 and KB7290 in a mass ratio of 1:1: 1. And mixing the first component, the second component and the third component in proportion to prepare the bisphenol A type benzoxazine resin for later use.
The epoxy casting insulating part of the embodiment is made of the benzoxazine modified epoxy resin insulating material, and the preparation method comprises the following steps:
1) preheating bisphenol A type epoxy resin with the formula amount at 130 ℃ for 0.5h, mixing the bisphenol A type epoxy resin with alumina filler at 130 ℃ for 0.5h, and carrying out degassing treatment under the conditions of 135 ℃ and a vacuum degree of 7mbar for 1.0h under heat preservation and pressure preservation to obtain a mixture A; the viscosity of the mixture A is not more than 7000 mPas;
2) preheating bisphenol A type benzoxazine resin for 0.5h at 65 ℃ and under the vacuum degree of 5 mbar;
mixing the mixture A with preheated bisphenol A type benzoxazine resin, and carrying out primary reaction for 0.5h at 135 ℃ under the vacuum degree of 7mbar to obtain a mixture B; the viscosity of the mixture B is not more than 7000 mPas;
3) preheating curing agent methyl tetrahydrophthalic anhydride for 0.5h at 65 ℃ and under the condition of vacuum degree of 5 mbar; preheating the die for 1.5h at 130 ℃;
mixing the mixture B with preheated curing agent methyl tetrahydrophthalic anhydride, pouring (static mixing type pouring) into a preheated mold under the conditions of 135 ℃ and 5mbar vacuum degree, keeping the temperature and pressure in an equipment pouring tank, standing for 5min, and conveying the mold from the pouring tank to a curing furnace for curing;
the curing adopts a three-stage curing process: preserving heat at 110 ℃ for 6.5h for first-stage curing, then heating to 120 ℃ and preserving heat for 4.5h for second-stage curing, then heating to 130 ℃ and preserving heat for 2.5h for third-stage curing, then closing a heating and blowing system of a curing oven, cooling to room temperature along with the oven without opening an oven door, demolding and finishing;
then constant temperature stress relief treatment is carried out: and (3) preserving the heat for 2.5 hours at the temperature of 130 ℃ under the condition of not applying external force to obtain the epoxy casting insulating part.
Example 4
The benzoxazine modified epoxy resin insulating material of the embodiment is prepared from a mixture of bisphenol a benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol a benzoxazine resin to the epoxy resin mixture is 1: 4.87; the epoxy resin mixture is composed of bisphenol A epoxy resin, a curing agent methyltetrahydrophthalic anhydride and an alumina filler (a mixture of A-F-3 type, A-F-4 type and A-F-5 type in a mass ratio of 1:1: 1), and the mass ratio of the bisphenol A epoxy resin, the curing agent methyltetrahydrophthalic anhydride and the alumina filler is 1:0.54: 3.3. The bisphenol A epoxy resin is CT 200M.
The bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1:2.5: 6.5; wherein, the component one is benzoxazine KB 4170; the component two is a mixture of benzoxazine KB6100 and KB6600 with the mass ratio of 10: 1; and the component III is a mixture of benzoxazine KB7280 and KB7290 in a mass ratio of 1: 10. And mixing the first component, the second component and the third component in proportion to prepare the bisphenol A type benzoxazine resin for later use.
The epoxy casting insulating part of the embodiment is made of the benzoxazine modified epoxy resin insulating material, and the preparation method comprises the following steps:
1) preheating bisphenol A type epoxy resin with the formula amount at 125 ℃ for 1.5h, mixing the bisphenol A type epoxy resin with alumina filler at 125 ℃ for 0.5h, and carrying out degassing treatment under the conditions of temperature preservation and pressure maintaining of 133 ℃ and vacuum degree of 6mbar for 2.0h to obtain a mixture A; the viscosity of the mixture A is not more than 7000 mPas;
2) preheating bisphenol A type benzoxazine resin for 0.5h at the temperature of 60 ℃ and the vacuum degree of 3 mbar;
mixing the mixture A with preheated bisphenol A type benzoxazine resin, and carrying out primary reaction for 0.5h at 130 ℃ under the vacuum degree of 6mbar to obtain a mixture B; the viscosity of the mixture B is not more than 7000 mPas;
3) preheating curing agent methyl tetrahydrophthalic anhydride for 0.5h at 55 ℃ and under the vacuum degree of 6 mbar; preheating the mould at 120 ℃ for 2.0 h;
mixing the mixture B with preheated curing agent methyl tetrahydrophthalic anhydride, pouring (static mixing type pouring) into a preheated mold under the conditions of 130 ℃ and 3mbar of vacuum degree, keeping the temperature and pressure in an equipment pouring tank, standing for 8min, and conveying the mold from the pouring tank to a curing furnace for curing;
the curing adopts a three-stage curing process: keeping the temperature at 115 ℃ for 6.5h for first-stage curing, then heating to 120 ℃ and keeping the temperature for 4.0h for second-stage curing, then heating to 135 ℃ and keeping the temperature for 2.0h for third-stage curing, then closing a heating and blowing system of a curing furnace, cooling to room temperature along with the furnace without opening a furnace door, demolding and finishing;
then constant temperature stress relief treatment is carried out: and (3) preserving the heat for 2.5 hours at 135 ℃ under the condition of not applying external force to obtain the epoxy casting insulating part.
Examples of the experiments
In this experimental example, an experimental sample and an epoxy cast insulator were prepared according to the preparation methods of the epoxy cast insulating members of examples 1 to 4, respectively, and the benzoxazine-modified epoxy resin insulating materials of examples 1 to 4 were subjected to measurement of glass transition temperature, bending strength, and breakdown strength, to verify the material properties; and performing a thermoelectric aging test on the insulator to verify the reliability of the insulator.
① glass transition temperature measurement, namely testing 5 samples according to GB/T22567-;
② bending strength, testing 5 samples according to the 5.3 th item in GB/T2567-2008, testing the temperature at 23 +/-2 ℃ and the bending rate at 10mm/min, and taking an average value;
③ breakdown Strength the test was carried out according to the method described in GB/T1408-2006, 10.1, with a test specimen diameter of 100mm and a thickness of 1mm, a test temperature of 23 + -2 ℃, SF of 0.4MPa6The procedure was carried out in gas at a rate of 500V/s, and 5 samples were tested using two symmetrical plate electrodes and averaged.
④ thermoelectric aging, according to the basic requirements of IEC TS 61251-2008, preparing an insulator with the diameter phi of 35 and the length of 150mm, wherein the specific pattern is shown in figure 1 (in figure 1, 1 is an insulator body, and metal inserts 2 are embedded at two ends), conducting a 105 ℃/100kV thermoelectric aging test in an oven with a lead-out silicone rubber insulator and an electrode loop, loading 200Nm bending load on one end electrode of the insulator in a manner shown in figure 2 (the two end surfaces of the insulator body 1, in which the metal inserts 2 are embedded, respectively abut against a fixing device 3 and a connecting block 4, and the bending load is loaded from one side of the connecting block 4), taking out the insulator every 24h, cooling, conducting a 500Nm/30min bending tolerance test, loading in a manner similar to that in figure 2, conducting colored flaw detection on the tested insulator insert and resin combining part, wherein the colored flaw detection part still has colored traces which are considered unqualified after being cleaned, otherwise, immediately stopping the thermoelectric aging test, and recording the thermoelectric aging test time of the thermoelectric aging test, subtracting 24h from the thermoelectric aging test time of the thermoelectric aging test, namely the insulator, which can be used as the pouring.
The results of the experiment are shown in table 1.
Wherein, the comparative example is an AC insulating material (mass ratio is 1:0.4:3.2, the curing process is 80 ℃/4h +140 ℃/10h, and the stress removing treatment process is 135 ℃/2h) which is poured by using epoxy resin of U.S. Hensmai B41CI type, curing agent of U.S. Hensmai HT903CI, and alumina mixture of electrical filler of type A-F-3 of light metal research institute of Zhengzhou of aluminum corporation in China.
TABLE 1 detection results of properties of benzoxazine-modified epoxy resin insulation materials and epoxy cast parts of examples 1 to 4
As can be seen from table 1, the glass transition temperature, the bending strength, and the breakdown strength of the benzoxazine-modified epoxy resin insulation materials of examples 1 to 4 were much higher than those of the comparative example, and the resulting epoxy cast insulator had a longer thermoelectric aging resistance time. The experimental result shows that compared with the prior art, the benzoxazine modified epoxy resin insulating material has higher glass transition temperature, bending strength and electrical strength, has better performance in a thermoelectric aging test, is suitable for a position of a high-voltage switch with higher mechanical load requirement and insulating property requirement, meets the requirement of insulator volume miniaturization, greatly improves the reliability and the service life of the insulator, and reduces the maintenance and overhaul cost of a power station.
Claims (10)
1. A benzoxazine modified epoxy resin insulating material is characterized in that: the composite material is prepared from a mixture of bisphenol A benzoxazine resin and epoxy resin, wherein the mass ratio of the bisphenol A benzoxazine resin to the epoxy resin is 1 (4.7-4.96); the epoxy resin mixture consists of bisphenol A epoxy resin, an aliphatic anhydride curing agent and an alumina filler, wherein the mass ratio of the bisphenol A epoxy resin to the aliphatic anhydride curing agent to the alumina filler is 1 (0.50-0.56) to 3.2-3.4.
2. The benzoxazine-modified epoxy insulation material according to claim 1, wherein: the bisphenol A benzoxazine resin is prepared by mixing a component I, a component II and a component III according to the mass ratio of 1 (2.5-3.5) to 5.5-6.5;
wherein, the component one is benzoxazine KB 4170;
the component two is any one or combination of benzoxazine KB6100 and KB 6600;
the component III is any one or combination of benzoxazine KB7165, KB7170, KB7200, KB7280 and KB 7290.
3. The benzoxazine-modified epoxy insulation material according to claim 1, wherein: the aliphatic anhydride curing agent is methyl tetrahydrophthalic anhydride.
4. An epoxy cast insulation component characterized by: the material of the epoxy cast insulation member is the benzoxazine modified epoxy insulation material according to any one of claims 1 to 3.
5. A method of making an epoxy cast insulation part according to claim 4, characterized in that: comprises the following steps:
1) preheating bisphenol A epoxy resin, mixing with an alumina filler at 125-135 ℃, and degassing to obtain a mixture A;
2) mixing the mixture A with preheated bisphenol A type benzoxazine resin, and reacting at 125-135 ℃ to obtain a mixture B;
3) and mixing the mixture B with the preheated aliphatic anhydride curing agent, pouring the mixture B into a preheated mold under the conditions of 125-135 ℃ and 2-5 mbar of vacuum degree, standing, curing and stress-relieving treatment.
6. The method of making an epoxy cast insulation part according to claim 5, characterized in that: in the step 1), the preheating temperature of the bisphenol A type epoxy resin is 120-130 ℃, and the preheating time is 0.5-1.5 h; in the step 2), preheating the bisphenol A benzoxazine resin at a preheating temperature of 55-65 ℃ for 0.5h under a vacuum degree of 2-5 mbar; in the step 3), the aliphatic anhydride curing agent is preheated under the condition that the vacuum degree is 2-5 mbar, the preheating temperature is 55-65 ℃, and the preheating time is 0.5 h.
7. The method of making an epoxy cast insulation part according to claim 5, characterized in that: in the step 1), the degassing treatment is heat preservation and pressure maintaining for 1.0-2.0 h at 125-135 ℃ and under the condition that the vacuum degree is 4-7 mbar.
8. The method of making an epoxy cast insulation part according to claim 5, characterized in that: and in the step 3), standing for 5-15 min under the condition of heat preservation and pressure maintaining.
9. The method of making an epoxy cast insulation part according to claim 5, characterized in that: in the step 3), the curing adopts a three-stage curing process: and (3) preserving heat for 5.5-6.5 h at 110-120 ℃ for the first-stage curing, then heating to 120-130 ℃ and preserving heat for 3.5-4.5 h for the second-stage curing, then heating to 130-140 ℃ and preserving heat for 1.5-2.5 h for the third-stage curing, then cooling to room temperature along with the furnace, and demolding.
10. The method of making an epoxy cast insulation part according to claim 5, characterized in that: in the step 3), the stress relief treatment refers to heat preservation for 1.5-2.5 hours at 130-140 ℃ under the condition of no external force.
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| CN117467333A (en) * | 2023-11-28 | 2024-01-30 | 济南市雋瀚电子材料有限公司 | High-heat-conductivity breakdown-voltage-resistant circuit board material, circuit board and preparation method thereof |
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| CN106832226A (en) * | 2015-12-04 | 2017-06-13 | 广东生益科技股份有限公司 | A kind of halogen-free epoxy resin composition and the prepreg containing it, laminate and printed circuit board |
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