Flame-retardant insulating powder as well as preparation method and application thereof

Abstract

The invention provides flame-retardant insulating powder. The flame-retardant insulating powder comprises the following raw materials in parts by weight: 100-120 parts of bisphenol A epoxy resin; 10 to 15 parts of a flame retardant; 100 to 120 parts of phthalic anhydride; 20 to 30 parts of epoxy chloropropane; 0.1 to 0.8 part of boron nitride; the flame retardant is a 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the flame retardant is a halogen-free flame retardant; wherein the weight part ratio of the bisphenol A epoxy resin to the phthalic anhydride is 1: 1. The invention also provides a preparation method and application of the flame-retardant insulating powder. The flame retardance of the flame-retardant insulating powder reaches V0 level, and the flame-retardant insulating powder has good breakdown strength and arc-resistant insulating performance.

Description

Technical Field

[0001] The invention relates to the technical field of insulating materials, and in particular to a flame retardant insulating powder and a preparation method and application thereof. Background Art

[0002] Insulating powders are widely used in the insulation of electrical components that require high voltage resistance, such as busbars, copper bars, circuit breakers, switch cabinets, insulators, bus ducts, and busbar insulation in switch cabinets. The use of flame-retardant insulating powders can improve the safety of equipment, reduce the volume of cabinets, and save costs. Insulating powders not only need to have good flame retardancy, but also need to have excellent temperature resistance, so that they can be widely used in the insulation of power equipment. However, traditional brominated flame retardants will produce harmful compounds during use, causing pollution and harm to the environment and human health. In order to overcome this problem, the use of new organic phosphorus-modified flame retardants has become an environmentally friendly and effective solution. These new flame retardants not only provide excellent flame retardancy, but also greatly reduce the impact on the environment, while having better overall performance.

[0003] Nowadays, researchers have conducted in-depth research on flame-retardant insulating powders. The Chinese patent document with publication number CN16462937A discloses a low-smoke, high-toughness epoxy resin and its preparation method. The epoxy resin composition includes bisphenol A epoxy resin, polypropylene glycol diglycidyl ether, butyl glycidyl ether, aluminum hydroxide, montmorillonite, modified glass fiber, polyethylene polyamine and tetramethyl ammonium chloride. Its key characteristics are good mechanical strength, toughness and low-smoke environmental performance. The Chinese patent document with publication number CN111073373A discloses a phosphating epoxy coating and its preparation method, including a mixture of fatty acid diethanolamine, sodium laurate soap, phosphoric acid-modified epoxy resin, glycerol tristearate, magnesium stearate, pyridine zinc and trimethylolpropane, wherein the phosphoric acid-modified epoxy resin is prepared by reacting epoxy resin E51, tetramethylsulfonic acid phosphate and other ingredients. The coating has good water dispersibility, antibacterial and antioxidant properties, and uniform film formation, and is highly safe to use. A Chinese patent document with publication number CN102633986A discloses a composition of an ultra-high voltage SF6 electrical insulating epoxy resin. Alumina filler is added to an epoxy resin system composed of MPE modified epoxy resin and MPH liquid anhydride curing agent, and a vacuum casting process or APG process is adopted to produce ultra-high voltage basin-type insulators or similar insulating products. The products have low heat release during curing, low curing heat release peak, small curing internal stress, high anti-cracking index, good stability, and are not prone to defects such as microcracks.

[0004] The product obtained by the above preparation method has poor insulation performance and does not have good flame retardancy. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to improve the flame retardancy of insulating powder while improving the breakdown strength and arc-resistant insulation performance.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] The first aspect of the present invention provides a flame retardant insulating powder, comprising the following raw materials in parts by weight:

[0008] 100-120 parts of bisphenol A epoxy resin; 10-15 parts of flame retardant; 100-120 parts of phthalic anhydride; 20-30 parts of epichlorohydrin; 0.1-0.8 parts of boron nitride; the flame retardant is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; wherein the weight ratio of bisphenol A epoxy resin to phthalic anhydride is 1:1.

[0009] Beneficial effect: The flame retardancy of the flame retardant insulating powder of the present invention reaches V0 level, and has good breakdown strength and arc-resistant insulation performance. If the weight ratio of bisphenol A epoxy resin to phthalic anhydride is not 1:1, the breakdown strength and arc-resistant insulation performance of the flame retardant insulating powder will be poor.

[0010] Preferably, the flame retardant insulating powder further comprises an additive, wherein the additive comprises silicon micropowder or silicon rubber, wherein the weight portion of the silicon micropowder is 0-8 parts, and the weight portion of the silicon rubber is 0-6 parts.

[0011] Beneficial effect: The present invention can save costs within a certain range by adding a small amount of additives.

[0012] The second aspect of the present invention provides a method for preparing the flame retardant insulating powder, comprising the following steps:

[0013] (1) preheating a bisphenol A epoxy resin, separating and purifying it after preheating to obtain a purified bisphenol A epoxy resin, mixing the purified bisphenol A epoxy resin with a flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with water, introducing chlorine gas for reaction, and obtaining a modified epoxy dispersion;

[0014] (2) The modified epoxy dispersion obtained in step (1) is mixed with phthalic anhydride and epichlorohydrin, and boron nitride is added thereto to obtain a mixed solution; the mixed solution is placed in a vacuum container for mixing, the mixed solution is discharged and cooled, and the mixture is ground with a grinder after cooling, and sieved to obtain a flame-retardant insulating powder.

[0015] Beneficial effects: The present invention purifies bisphenol A epoxy resin to solve the problems of reduced heat resistance and generation of curing reaction by-products caused by impurities in bisphenol A epoxy resin, and uses the purified bisphenol A epoxy resin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide for organic modification synthesis, and connects 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide into the molecular structure of bisphenol A epoxy resin through chemical reaction, which will not affect the viscosity and performance of the formula system, and can also prepare insulating powder with flame retardancy reaching V0 level, and has good breakdown strength and arc-resistant insulation performance.

[0016] Preferably, in step (2), an additive is added to the mixed liquid, the mixture is mixed and then placed in a vacuum container, and the additive is silicon micropowder or silicone rubber.

[0017] Preferably, the preheating temperature is 80-90°C and the time is 30-40 minutes.

[0018] Preferably, the specific operation of separation and purification of the bisphenol A epoxy resin is to send the preheated bisphenol A epoxy resin into a vacuum container for separation and purification twice, and the temperatures of the two separation and purification are 110-115° C. and 130-140° C. respectively.

[0019] Beneficial effects: The present invention separates and purifies the bisphenol A epoxy resin twice, thereby avoiding the problem of adding diluents in traditional purification methods that leads to a decrease in the glass transition temperature and long-term thermal life of the epoxy resin, and effectively removes by-products produced by the polymerization reaction of the epoxy resin, reducing impurities in the bisphenol A epoxy resin.

[0020] Preferably, in step (1), the reaction temperature is 60-70° C. and the reaction time is 1.5-2 h.

[0021] Preferably, in step (2), the temperature in the vacuum container is 110-130° C., the pressure is 20-30 Pa, and the mixing time is 2-2.5 h.

[0022] Preferably, the pressure of the two separation and purification steps is 20-30 Pa.

[0023] The third aspect of the present invention provides the use of the flame retardant insulating powder in electric power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the preparation principle of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the preparation example;

[0025] Figure 2 is the chemical reaction equation of step (2) in Example 1;

[0026] Figure 3 This is a temperature change resistance test diagram of the flame retardant insulating powder of Example 1;

[0027] Figure 4 This is a temperature change test diagram of the flame retardant insulating powder of comparative example 1; the lines in the figure indicate that the cured product cracks in the fourth cycle;

[0028] Figure 5 This is a temperature change test diagram of the flame retardant insulating powder of comparative example 2; the lines in the figure indicate that the cured product cracks in the fifth cycle;

[0029] Figure 6 This is a temperature change test diagram of the flame retardant insulating powder of comparative example 6; the lines in the figure indicate that the cured product cracks in the fourth cycle;

[0030] Figure 7 This is a temperature change resistance test diagram of the flame retardant insulating powder of comparative example 7; the lines in the figure indicate that the cured product cracked in the fifth cycle. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0033] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0034] Preparation Example

[0035] The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO used in this example can be purchased from the market or prepared by oneself. The preparation principle is as follows: Figure 1 As shown, the preparation method is as follows:

[0036] (1) Use anhydrous ethanol to recrystallize industrial o-phenylphenol OPP to obtain pure o-phenylphenol.

[0037] (2) In a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 10-40 parts of o-phenylphenol, 10-30 parts of PCl3 and 0.05-0.12 parts of ZnCl2 are added. When the temperature is raised to 30-40°C, the o-phenylphenol dissolves. When the temperature is raised to 40-50°C, HCl gas is released. When the temperature is raised to 100-140°C, 5-15 parts of PCl3 are slowly added dropwise to the container. Finally, the temperature is raised to 180-250°C and the reaction is carried out at a constant temperature for 1.5-2 hours to obtain an oxaphosphorin solution CDOP.

[0038] (3) The above solution is cooled to 90-110°C, 60-70 parts of chlorobenzene are added, cooled to room temperature and then heated, 30-40 parts of distilled water are added dropwise, the temperature is raised to 60-80°C and the reaction is carried out at a constant temperature for 2-4 hours, the oil layer is separated at 80-100°C, 10-14 parts of 50-70°C distilled water are added and the reaction is continued for 0.5-1.5 hours, and the reaction is repeated 2-5 times. The oil layer obtained in the last step is cooled to precipitate a white crystalline solid, which is filtered and washed with water to obtain pure 2'-hydroxybiphenyl-2-phosphorous acid HBP.

[0039] (4) 2'-hydroxybiphenyl-2-phosphorous acid is heated to a molten state, and the temperature is slowly raised to 140-180° C. at 10000-15000 Pa to stop the dehydration reaction. After cooling to 40-60° C., the solution is recrystallized from tetrahydrofuran to obtain pure 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO.

[0040] Example 1

[0041] This embodiment provides a flame retardant insulating powder, comprising the following raw materials in parts by weight:

[0042] 110 parts of bisphenol A epoxy resin; 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 110 parts of phthalic anhydride; 25 parts of epichlorohydrin; 0.3 parts of boron nitride; 3.5 parts of silicon powder; 3.5 parts of silicone rubber; the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is prepared according to the preparation example.

[0043] The method for preparing the flame-retardant insulating powder specifically comprises the following steps:

[0044] (1) 110 parts by weight of bisphenol A epoxy resin are preheated at 80° C. for 30 minutes, and then 2.66 parts by weight of bisphenol A epoxy resin are introduced into a vacuum container for two separation and purifications at an amount of 2.66 parts by weight per hour. The temperature of the vacuum container for the first separation and purification is controlled at 110° C., and the temperature of the vacuum container for the second separation and purification is controlled at 130° C. The pressure of both separation and purifications is 20 Pa, thereby obtaining purified bisphenol A epoxy resin.

[0045] (2) The purified bisphenol A epoxy resin and 12.5 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed with deionized water, wherein the amount of deionized water added was 20 times the weight of the purified bisphenol A epoxy resin, and stirred at 1500 rpm for 15 min. The mixture was fed into a reactor and chlorine gas was introduced for reaction. The specific chemical reaction equation is as follows: Figure 2 As shown, the mixture was stirred at 60°C for 1.5 hours, then discharged and cooled to obtain a modified epoxy dispersion.

[0046] (3) The modified epoxy dispersion obtained in step (2) is dispersed with 110 parts by weight of phthalic anhydride and 25 parts by weight of epichlorohydrin at a speed of 1000 rpm for 20 min, 3.5 parts by weight of silicon micropowder, 0.3 parts by weight of boron nitride and 3.5 parts by weight of silicone rubber are added, and the dispersion is continued at a speed of 1000 rpm for 10 min. The uniformly dispersed mixed solution is sent into a vacuum container, the temperature is controlled at 110° C. and the pressure is 20 Pa, and the mixture is mixed for 2 hours, and then the material is discharged and cooled.

[0047] (4) Grind the cooled material with a grinder to a fineness of ≤20 μm, stir evenly, and filter with a 100-mesh filter to obtain a flame-retardant insulating powder.

[0048] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0049] Example 2

[0050] The present embodiment provides a flame retardant insulating powder. The difference between the present embodiment and the embodiment 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 100 parts of bisphenol A epoxy resin, 10 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 100 parts of phthalic anhydride, 20 parts of epichlorohydrin, 1 part of silicon micropowder, 0.1 parts of boron nitride and 2 parts of silicone rubber.

[0051] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0052] Example 3

[0053] The present embodiment provides a flame retardant insulating powder. The difference between the present embodiment and the embodiment 1 is that the weight parts of the raw materials added are different, and the preparation method is the same, which is as follows: 120 parts of bisphenol A epoxy resin, 15 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 120 parts of phthalic anhydride, 30 parts of epichlorohydrin, 6 parts of silicon micropowder, 0.5 parts of boron nitride and 5 parts of silicone rubber.

[0054] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0055] Example 4

[0056] This embodiment provides a flame retardant insulating powder. The difference between this embodiment and embodiment 1 is that the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in this embodiment is commercially available.

[0057] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0058] Example 5

[0059] The present embodiment provides a flame retardant insulating powder. The difference between the present embodiment and the embodiment 1 is that the weight parts of the raw materials added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 8 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0060] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0061] Example 6

[0062] This embodiment provides a flame retardant insulating powder. This embodiment differs from Embodiment 1 in that silicon powder is not added, the preparation method is the same, and the weight portions of other raw materials added remain unchanged.

[0063] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0064] Example 7

[0065] The present embodiment provides a flame retardant insulating powder. The difference between the present embodiment and the embodiment 1 is that the weight parts of the raw materials added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.8 parts of boron nitride and 3.5 parts of silicone rubber.

[0066] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0067] Example 8

[0068] This embodiment provides a flame retardant insulating powder. This embodiment differs from Embodiment 1 in that silicone rubber is not added, the preparation method is the same, and the weight portions of other raw materials added remain unchanged.

[0069] The flame retardant insulating powder of this embodiment was tested for performance, and specific data are shown in Table 1.

[0070] Comparative Example 1

[0071] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 140 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0072] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0073] Comparative Example 2

[0074] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 80 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0075] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0076] Comparative Example 3

[0077] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0078] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0079] Comparative Example 4

[0080] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 20 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0081] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0082] Comparative Example 5

[0083] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is not added, the preparation method is the same, and the weight parts of other raw materials added remain unchanged.

[0084] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0085] Comparative Example 6

[0086] This comparative example provides a method for preparing a flame retardant insulating powder and the obtained flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 80 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0087] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0088] Comparative Example 7

[0089] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 140 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0090] The flame retardant insulating powder was prepared in this comparative example, and the specific data of the performance test are shown in Table 1.

[0091] Comparative Example 8

[0092] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 15 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0093] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0094] Comparative Example 9

[0095] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of each raw material added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 35 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 3.5 parts of silicone rubber.

[0096] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0097] Comparative Example 10

[0098] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that no boron nitride is added, the preparation method is the same, and the weight parts of other raw materials added remain unchanged.

[0099] The specific data of the performance test of the flame retardant insulating powder of this comparative example are shown in Table 1.

[0100] Comparative Example 11

[0101] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the weight parts of the raw materials added are different, and the preparation method is the same, which is as follows: 110 parts of bisphenol A epoxy resin, 12.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 110 parts of phthalic anhydride, 25 parts of epichlorohydrin, 3.5 parts of silicon micropowder, 0.3 parts of boron nitride and 8 parts of silicone rubber.

[0102] Comparative Example 12

[0103] This comparative example provides a method for preparing a flame-retardant insulating powder. The difference between this comparative example and Example 1 is that the bisphenol A epoxy resin is not separated and purified, and the weight parts of each raw material added are the same as those in Example 1.

[0104] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0105] Comparative Example 13

[0106] This comparative example provides a method for preparing a flame-retardant insulating powder. The difference between this comparative example and Example 1 is that the bisphenol A epoxy resin is only separated and purified for the first time, and the weight portion of each raw material added is the same as that in Example 1.

[0107] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0108] Comparative Example 14

[0109] This comparative example provides a flame retardant insulating powder. The difference between this comparative example and Example 1 is that the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is replaced by decabromodiphenyl ether, and the preparation method is the same.

[0110] The flame retardant insulating powder of this comparative example was subjected to performance test, and specific data are shown in Table 1.

[0111] Performance testing

[0112] The flame retardant insulating powders prepared in Examples 1-8 and Comparative Examples 1-14 were subjected to performance tests.

[0113] Flame retardancy (UL-94@1.5mm): GB / T2408-2008 test method is used for testing. The instrument used for flame retardancy is a horizontal vertical combustion tester, model SCRS-A. Specific testing method: Place the cured product in the horizontal vertical combustion tester for testing.

[0114] Breakdown strength test: Use a 25mm diameter cylindrical electrode as a high-voltage electrode and a copper sheet as a grounding electrode, and then use a power frequency voltage breakdown tester (model NDB-B) to measure the breakdown strength of the cured product. The test is carried out at room temperature 25°C, and an AC voltage is applied to the high-voltage end of the electrode until the sample breaks down. The voltage increase rate is 1kV / s, and each sample is measured 10 times.

[0115] Arc resistance test: The test is conducted in accordance with GB / T 1411-2002. The arc resistance test is conducted using an arc resistance test machine, model DDJ-100KV. Specific test method: The solidified material is tested using an arc resistance test machine.

[0116] Temperature change resistance test: GB / T 2423.22 test method is used for testing. The temperature change resistance test uses a high and low temperature alternating humidity and heat test chamber, model LS-GDH-150R. Specific test method: The cured product is tested using a high and low temperature alternating humidity and heat test chamber.

[0117] The solidified product is obtained by coating one side of the copper busbar with flame retardant insulating powder and then solidifying it.

[0118] Tensile performance test: GB / T1040-2006 test method is used for testing. The tensile performance is tested using a universal material testing machine, model: CTM-100GD. Specific test method: The flame retardant insulating powder is passed through a mold to obtain a test sample, the test sample size is 80mm*10mm*4mm, the gauge length is 50mm, and then the tensile strength is tested using a universal material testing machine.

[0119] Bending strength test: GB / T9341-2008 test method is used for testing. The bending strength test uses a universal material testing machine, model: CTM-100GD. Specific test method: The flame-retardant insulating powder is passed through a mold to obtain a test sample, and then unconstrained support is used to bend the test sample through three-point bending at a constant loading rate to destroy the test sample or reach a predetermined displacement value.

[0120] Table 1 Test data of flame retardant insulating powder

[0121]

[0122]

[0123] It can be seen from Table 1 that through the data analysis of Examples 1-8, when the weight of the raw materials is within a certain protection range, the flame retardant insulating powder has excellent flame retardant effect and good breakdown strength and arc resistance insulation performance, the flame retardancy can reach V0 level, the breakdown strength can reach above 32.9 kV / mm, and the arc resistance can reach above 178s.

[0124] By comparing Examples 1-3 with Example 4, it is found that the self-prepared 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide has the same effect as the commercially available 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0125] Through the data analysis of Example 1 and Comparative Examples 1-14, since one component in the weight of the raw materials of Comparative Examples 1-14 is not within the protection range, the flame retardancy level will be reduced or unqualified, and the breakdown strength or arc resistance insulation performance will be reduced.

[0126] Compared with Comparative Examples 1 and 6, firstly, the weight ratio of bisphenol A epoxy resin to phthalic anhydride in Comparative Examples 1 and 6 is not 1:1. Too much bisphenol A epoxy resin is added in Comparative Example 1, and too little phthalic anhydride is added in Comparative Example 6, which will cause the flame-retardant insulating powder to be incompletely cured during use, resulting in reduced breakdown strength and arc resistance, thereby resulting in poor insulation performance; at the same time, it will also lead to poor temperature change resistance, such as Figure 2 As shown, the cured product of Comparative Example 1 cannot pass the fourth cycle test when the temperature change resistance test is performed; Figure 4 As shown, the cured product of Comparative Example 6 cannot pass the fourth cycle test when subjected to the temperature change resistance test.

[0127] Compared with Comparative Examples 2 and 7, Example 1 has too much phthalic anhydride added in Comparative Example 2 and too little bisphenol A epoxy resin added in Comparative Example 7. Although the curing speed of bisphenol A epoxy resin is accelerated, a small amount of unreacted phthalic anhydride small molecules remain after curing. These small molecules have high mobility and polarity, which can easily lead to increased leakage current or even local breakdown under the action of an electric field. Therefore, the breakdown strength and arc resistance insulation performance are poorer than those of Example 1. The residual phthalic anhydride not only weakens the stability of the cross-linked network, but also destroys the uniformity of the cross-linked network due to excessive addition, forming low cross-linking density areas or structural defects, resulting in poor mechanical properties and temperature resistance of the cured flame-retardant insulating powder. Figure 3 As shown, the cured product of Comparative Example 2 cannot pass the fifth cycle test when the temperature change resistance test is performed; Figure 5 As shown, the cured product of Comparative Example 7 cannot pass the fifth cycle test when subjected to the temperature change resistance test.

[0128] Compared with Comparative Examples 3-5, the raw material components of the flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide added in Comparative Examples 3, 4 and 5 are not within the protection range, wherein less flame retardant is added in Comparative Example 3, resulting in its flame retardant performance only reaching V1 level; no flame retardant is added in Comparative Example 5, resulting in the flame retardant insulating powder not having flame retardant performance; more flame retardant is added in Comparative Example 4, which will result in residual small molecules and unreacted strongly polarized groups, resulting in reduced breakdown strength and arc resistance insulation performance of the flame retardant insulating powder.

[0129] Compared with Comparative Examples 8 and 9, in Example 1, the raw material of epichlorohydrin in Comparative Example 8 is not within the protection scope. Epichlorohydrin, as a cross-linking agent, can combine the modified epoxy molecules in the modified epoxy dispersion to make the structure of the flame-retardant insulating powder more compact. Adding less or more epichlorohydrin will lead to a decrease in the breakdown strength and arc resistance of the flame-retardant insulating powder.

[0130] Compared with Example 10, the raw material components of boron nitride in Example 10 are not within the protection range. Boron nitride is added to the flame retardant insulating powder as a filler, so that the flame retardant insulating powder has a low dielectric constant, high volume resistivity and high electrical strength. The lack of addition of boron nitride in Example 10 leads to a decrease in the breakdown strength and arc resistance insulation performance of the flame retardant insulating powder.

[0131] Compared with Example 11, the raw material components of the silicone rubber in Example 11 are not within the protection range. Silicone rubber is added to the flame retardant insulating powder as an additive to improve the toughness of the flame retardant insulating powder cured product and solve the problem of brittle texture of bisphenol A epoxy resin. However, excessive addition will lead to a decrease in the breakdown strength and arc resistance of the flame retardant insulating powder.

[0132] Compared with Example 12, in Example 12, the bisphenol A epoxy resin was not separated and purified, and some impurities contained therein, such as water and organic solvents, would volatilize during the curing process, resulting in foaming, and thus reducing the breakdown strength and arc-resistant insulation performance of the flame-retardant insulating powder.

[0133] Compared with Example 13, in Example 13, only the first separation and purification of bisphenol A epoxy resin is performed, resulting in insufficient separation and purification. Although the first separation removes low-boiling impurities such as water and organic solvents, some high-boiling polymer impurities are still left therein and have not been removed. For example, residual epichlorohydrin is unstable in a hot and humid environment, so the flame-retardant insulating powder is prone to generate Cl when heated. - These by-products and ionic impurities will cause the breakdown strength and arc resistance of flame-retardant insulating powder to decrease.

[0134] Compared with Example 14, although the flame retardant and insulating properties of Example 14 are equivalent, the flame retardant in Example 14 is decabromodiphenyl ether, which contains more than 82% bromine and can effectively capture free radicals in the combustion reaction. However, when decabromodiphenyl ether burns, it decomposes to produce smoke and toxic gases that are harmful to the human body and the environment, which does not meet environmental protection requirements.

[0135] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flame retardant insulating powder, characterized in that: The invention comprises the following raw materials in parts by weight: 100-120 parts of bisphenol A epoxy resin; 10-15 parts of flame retardant; 100-120 parts of phthalic anhydride; 20-30 parts of epichlorohydrin; 0.1-0.8 parts of boron nitride; the flame retardant is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; wherein the weight ratio of bisphenol A epoxy resin to phthalic anhydride is 1:

1.

2. The flame retardant insulating powder according to claim 1, characterized in that: The invention also comprises an additive, wherein the additive is silicon micropowder or silicon rubber, the weight portion of the silicon micropowder is 0-8 parts, and the weight portion of the silicon rubber is 0-6 parts.

3. The method for preparing flame-retardant insulating powder according to claim 1 or 2, characterized in that: The following steps are involved: (1) preheating a bisphenol A epoxy resin, separating and purifying it after preheating to obtain a purified bisphenol A epoxy resin, mixing the purified bisphenol A epoxy resin with a flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with water, introducing chlorine gas for reaction, and obtaining a modified epoxy dispersion; (2) The modified epoxy dispersion obtained in step (1) is mixed with phthalic anhydride and epichlorohydrin, and boron nitride is added thereto to obtain a mixed solution; the mixed solution is placed in a vacuum container for mixing, the mixed solution is discharged and cooled, and the mixture is ground with a grinder after cooling, and sieved to obtain a flame-retardant insulating powder.

4. The method for preparing flame-retardant insulating powder according to claim 3, characterized in that: In the step (2), an additive is added to the mixed liquid, the mixture is mixed and then placed in a vacuum container, and the additive is silicon micropowder or silicone rubber.

5. The method for preparing flame-retardant insulating powder according to claim 3, characterized in that: The preheating temperature is 80-90°C and the preheating time is 30-40 minutes.

6. The method for preparing flame-retardant insulating powder according to claim 3, characterized in that: The specific operation of separation and purification of the bisphenol A epoxy resin is to send the preheated bisphenol A epoxy resin into a vacuum container for two separation and purifications, and the two separation and purification temperatures are 110-115° C. and 130-140° C. respectively.

7. The method for preparing flame-retardant insulating powder according to claim 3, characterized in that: In the step (1), the reaction temperature is 60-70° C. and the reaction time is 1.5-2 h.

8. The method for preparing flame-retardant insulating powder according to claim 3, characterized in that: In the step (2), the temperature in the vacuum container is 110-130° C., the pressure is 20-30 Pa, and the mixing time is 2-2.5 h.

9. The method for preparing flame-retardant insulating powder according to claim 6, characterized in that: The pressure of both separation and purification was 20-30Pa.

10. Use of the flame-retardant insulating powder according to claim 1 or 2 in electric power equipment.

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