Bromine-containing epoxy resin reinforced insulation board and production method thereof

Abstract

The invention relates to the technical field of epoxy resin plates, and particularly discloses a bromine-containing epoxy resin enhanced insulating plate and a production method thereof. The bromine-containing epoxy resin enhanced insulating plate is formed by curing and pressing after a base material is soaked in a glue solution, and the glue solution comprises 100 parts of brominated epoxy resin, 5-10 parts of nano toughened epoxy resin, 5-10 parts of phenol novolac epoxy resin, 10-30 parts of a curing agent, 0.1-1 part of an accelerant, 30-50 parts of inorganic filler, 1-3 parts of an organic flame retardant and 15-20 parts of dimethyl sulfoxide. The base material is selected from at least one of a glass fiber felt, a carbon fiber felt, a Kevlar fiber felt and an aromatic polyamide paper fiber felt. The insulating plate prepared by the invention has relatively high peel strength, heat resistance and humidity and heat resistance, and also has good dielectric properties and flame retardancy.

Description

Technical Field

[0001] The present invention relates to a brominated epoxy resin reinforced insulating board and a production method thereof, belonging to the technical field of electrical insulating materials, and is particularly applicable to occasions with high requirements for insulation performance, mechanical performance and flame retardancy in industries such as electronic appliances, aviation, ships, and buildings. Background Art

[0002] The insulating board made of brominated epoxy resin is an insulating material part with self-extinguishing function and good heat resistance. Brominated epoxy resin is made from epoxy resin containing bromine element, also known as brominated epoxy resin or brominated epoxy resin. The bromine content of this type of resin is usually between 19% and 50%, and the softening point range is between 51 and 100 degrees Celsius. This resin not only has excellent electrical insulation and adhesion of general epoxy resin, but also has excellent flame retardancy and does not produce dioxin problems, and has become an important substitute for decabromodiphenyl ether.

[0003] As an important electrical insulating material, insulating boards are widely used in industries such as construction, aviation, ships, and electronic appliances. In practical applications, insulating boards need to have good electrical insulation, mechanical properties, heat resistance and flame retardancy. Although traditional epoxy resin insulating boards have certain insulation performance, there are still problems with insufficient performance in high-end applications.

[0004] In order to overcome the performance limitations of traditional insulating boards, the industry has been exploring preparation methods for enhanced insulating boards. Enhanced insulating boards usually improve their mechanical properties, heat resistance and flame retardancy by adding reinforcing fillers and optimizing preparation processes. For example, using silica and calcium powder as reinforcing fillers can significantly improve the mechanical strength of insulating boards. At the same time, by precisely controlling various parameters in the preparation process, such as reaction temperature, time, raw material ratio, etc., the relative molecular mass of brominated epoxy resin can be effectively increased, thereby improving the overall performance of insulating boards.

[0005] Existing epoxy resin insulating boards have some limitations in performance. For example, the relative molecular mass of traditional epoxy resin is relatively low, which may lead to the risk of bleeding glue, thereby affecting the dimensional stability and mechanical properties of insulating boards. In addition, traditional insulating boards are also difficult to meet the requirements of some high-end applications in terms of flame retardancy and heat resistance. Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a brominated epoxy resin reinforced insulating board and a production method thereof. The present application uses self-made brominated epoxy resin, which has a narrow molecular weight distribution and a high glass transition temperature, and the prepared insulating board has excellent heat resistance and mechanical properties.

[0007] In a first aspect, the present application provides a brominated epoxy resin reinforced insulating board, adopting the following technical solution:

[0008] A brominated epoxy resin reinforced insulating board is formed by curing and pressing a base material impregnated with a sizing solution. The sizing solution includes 100 parts of brominated epoxy resin, 5 - 10 parts of nano - toughened epoxy resin, 5 - 10 parts of phenol - formaldehyde epoxy resin, 10 - 30 parts of curing agent, 0.1 - 1 part of accelerator, 30 - 50 parts of inorganic filler, 1 - 3 parts of organic flame retardant, and 15 - 20 parts of dimethyl sulfoxide.

[0009] The brominated epoxy resin can improve the adhesion and high glass transition temperature of the sizing solution, and improve the flame - retardant performance of the insulating board. The addition of nano - toughened epoxy resin and phenol - formaldehyde epoxy resin can significantly enhance the toughness and strength of the insulating board.

[0010] Preferably, the curing agent is at least one of amine - type curing agents and anhydride - type curing agents.

[0011] Among them, the amine - type curing agent can specifically be selected from aliphatic amines such as ethylenediamine, diethylenetriamine, polyethylenepolyamine, etc.; or aromatic amines such as m - phenylenediamine, m - xylylenediamine, etc.; or amine - modified curing agents such as T31 curing agent, phenolic amino alcohol curing agent, etc., or latent curing agents such as dicyandiamide. The anhydride - type curing agent can specifically be selected from organic acid anhydrides such as maleic anhydride, phthalic anhydride, etc.

[0012] The accelerator is selected from one or a combination of phenolic accelerators, imidazole accelerators, amine accelerators, and Lewis acid accelerators.

[0013] Among them, phenolic accelerators include but are not limited to phenol, resorcinol, nonylphenol, bisphenol A, and 2,4,6 - tris(dimethylaminomethyl)phenol, etc.; amine accelerators include but are not limited to o - hydroxybenzyl dimethylamine, triethylamine, triethanolamine, benzyl dimethylamine, and alkyltrimethyl ammonium bromide salts, etc.; imidazole accelerators include but are not limited to 2 - methylimidazole and 2 - phenylimidazole, etc.; Lewis acid accelerators include but are not limited to BF3, SnCl4, AlCl3, FeCl3, TiCl4, and ZnCl2, etc.

[0014] The base material is selected from at least one of glass fiber felt, carbon fiber felt, Kevlar fiber felt, and aromatic polyamide paper fiber felt.

[0015] Further, the inorganic filler is selected from one or more of silica, alumina, titanium dioxide, and glass powder.

[0016] Further, the organic flame retardant is a phosphorus - based flame retardant and / or a halogen - based flame retardant.

[0017] Among them, the phosphorus-based flame retardants include, but are not limited to, tris(2,6-dimethylphenyl)phosphine, resorcinol bis[bis(2,6-dimethylphenyl)phosphate], resorcinol tetraphenyl diphosphate, triphenyl phosphate, bisphenol A bis(diphenyl phosphate), phosphazene flame retardants, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide flame retardants, etc.

[0018] The halogen-based flame retardant is a bromine-based flame retardant, including, but are not limited to, decabromodiphenyl ether, brominated polystyrene, brominated polycarbonate, tetrabromobisphenol A, decabromodiphenylethane, and ethylene bis(tetrabromophthalimide), etc.

[0019] Among them, the preparation method of the brominated epoxy resin is as follows: Epichlorohydrin and tetrabromobisphenol A are added to a solvent, and after heating and dissolving, a composite catalyst is added, and the reaction is carried out by heating for 1.5 - 2 h. Then boron trifluoride-ethyl ether complex is added and the reaction continues for 1.5 - 2 h. After the reaction is completed, an aqueous alkali solution is added, and the reaction is carried out by heating for 2 - 3 h. After the reaction is completed, an acid solution is added for neutralization and filtration, and the solvent is removed to obtain the brominated epoxy resin.

[0020] Furthermore, the mass ratio of the tetrabromobisphenol A, epichlorohydrin, and the solvent is 1:(0.2 - 0.4):(0.2 - 0.6), preferably 1:0.35:0.5.

[0021] Furthermore, the solvent is selected from at least one of diethylene glycol dimethyl ether, isopropanol, methyl isobutyl ketone, toluene, xylene, acetone, and n-butanol.

[0022] Furthermore, the composite catalyst is composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate mixed in a mass ratio of 1:(0.8 - 1.2), preferably 1:1.

[0023] Furthermore, based on the mass of the tetrabromobisphenol A, the addition amount of the composite catalyst is 0.5 - 2 wt%, preferably 1.5 wt%.

[0024] Furthermore, based on the mass of the tetrabromobisphenol A, the addition amount of the boron trifluoride-ethyl ether complex is 0.05 - 1 wt%, preferably 1 wt%.

[0025] The boron trifluoride-ethyl ether complex belongs to a Lewis acid catalyst and has strong Lewis acidity. In this application, it is used in the synthesis of brominated epoxy resin, which can inhibit the formation of branched chains, precisely control the molecular weight distribution during the synthesis process, and significantly narrow the molecular weight distribution range.

[0026] Further, the liquid caustic soda is a 50% concentration NaOH solution. Based on the mass of tetrabromobisphenol A, the addition amount of the liquid caustic soda is 15 - 20 wt%, preferably 20 wt%.

[0027] The addition of the liquid caustic soda mainly promotes the etherification reaction, accelerates the etherification reaction between tetrabromobisphenol A and epichlorohydrin, and helps to improve the selectivity of the reaction, reduce the occurrence of side reactions, thereby improving the purity and quality of the brominated epoxy resin.

[0028] In a second aspect, the present application provides a production method of a brominated epoxy resin reinforced insulating board, adopting the following technical solution:

[0029] A production method of a brominated epoxy resin reinforced insulating board, the specific steps are: infiltrating the base material with the sizing solution, heating and volatilizing the solvent to obtain a semi-cured film, stacking and pressing multiple films to make the brominated epoxy resin reinforced insulating board.

[0030] The sizing solution is obtained by mixing and stirring evenly brominated epoxy resin, nano-toughened epoxy resin, phenol novolac epoxy resin, curing agent, accelerator, inorganic filler, organic flame retardant and dimethyl sulfoxide.

[0031] The base material is selected from at least one of fiberglass mat, carbon fiber mat, Kevlar fiber mat and aromatic polyamide paper fiber mat.

[0032] In the present application, the self-made brominated epoxy resin is used as the matrix resin, and nano-toughened epoxy resin and phenol novolac epoxy resin are compounded. Its cured product has a high glass transition temperature, and the insulating board prepared therefrom has the characteristics of high toughness and high strength. The present application adopts a composite catalyst system composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate, introduces boron trifluoride-ether complex, and optimizes the preparation steps of brominated epoxy resin. The prepared brominated epoxy resin has no free bromine residue, narrow molecular weight distribution and relatively high thermal stability. Specific Embodiments

[0033] The following specific examples illustrate the embodiments of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application.

[0034] In addition, it should be understood that one or more method steps mentioned in this application do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is only a convenient tool for identifying each method step, rather than restricting the arrangement order of each method step or limiting the scope of implementation of this application. The change or adjustment of its relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of this application.

[0035] If the specific experimental conditions are not specified in the examples, they are usually in accordance with the conventional conditions in the art or the conditions recommended by the reagent company; the materials, reagents, etc. used in the examples, unless otherwise specified, can be obtained through commercial channels.

[0036] Caustic soda solution: 50% mass concentration sodium hydroxide aqueous solution.

[0037] Phosphoric acid solution: 30% mass concentration phosphoric acid aqueous solution.

[0038] Boron trifluoride-ether complex: molar ratio BF3:C2H6O = 1:1.

[0039] Nanotoughened epoxy resin: purchased from Sinopec Hunan Petrochemical Co., Ltd., brand CYDN-128, epoxy equivalent 200-220 g / eq.

[0040] Phenol novolac epoxy resin: purchased from Sinopec Hunan Petrochemical Co., Ltd., brand CYDPN-048, epoxy equivalent 190-210 g / eq.

[0041] Examples 1-6: Preparation of brominated epoxy resin.

[0042] Preparation of brominated epoxy resin in Example 1:

[0043] Epichlorohydrin, tetrabromobisphenol A, and methyl isobutyl ketone solvent were mixed and dissolved in a mass ratio of 1:0.2:0.2, and a composite catalyst composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate in a weight ratio of 1:0.8 was added. The amount of the composite catalyst was 0.5% of the weight of tetrabromobisphenol A. It was heated to 70 °C and subjected to the first reaction for 2 h;

[0044] After the first reaction was completed, boron trifluoride-ether complex was added. The amount of boron trifluoride-ether complex was 0.05% of the weight of tetrabromobisphenol A. The temperature was maintained and the second reaction was carried out for 2 h;

[0045] After the second reaction was completed, a 50% mass concentration caustic soda solution was added. The amount of the caustic soda solution was 15% of the weight of tetrabromobisphenol A. It was heated to 98 °C and subjected to the third reaction for 2.5 h;

[0046] After the third reaction is completed, neutralize to pH = 7-8 with a phosphoric acid solution having a mass concentration of 30%, separate the liquid and filter to remove salts, and after removing the solvent, the brominated epoxy resin is obtained.

[0047] Preparation of brominated epoxy resin in Example 2:

[0048] Epichlorohydrin, tetrabromobisphenol A, and methyl isobutyl ketone solvent are mixed and dissolved in a mass ratio of 1:0.3:0.35. A composite catalyst composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate in a weight ratio of 1:1 is added. The amount of the composite catalyst used is 1.5% of the weight of tetrabromobisphenol A. Heat to 70 °C and carry out the first reaction for 2 h;

[0049] After the first reaction is completed, boron trifluoride-ether complex is added. The amount of boron trifluoride-ether complex used is 0.05% of the weight of tetrabromobisphenol A. Keep the temperature and carry out the second reaction for 2 h;

[0050] After the second reaction is completed, a liquid caustic soda solution with a mass concentration of 50% is added. The amount of the liquid caustic soda solution used is 15% of the weight of tetrabromobisphenol A. Heat to 98 °C and carry out the third reaction for 2.5 h;

[0051] After the third reaction is completed, neutralize to pH = 7-8 with a phosphoric acid solution having a mass concentration of 30%, separate the liquid and filter to remove salts, and after removing the solvent, the brominated epoxy resin is obtained.

[0052] Preparation of brominated epoxy resin in Example 3:

[0053] Epichlorohydrin, tetrabromobisphenol A, and methyl isobutyl ketone solvent are mixed and dissolved in a mass ratio of 1:0.4:0.6. A composite catalyst composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate in a weight ratio of 1:1.2 is added. The amount of the composite catalyst used is 2% of the weight of tetrabromobisphenol A. Heat to 70 °C and carry out the first reaction for 2 h;

[0054] After the first reaction is completed, boron trifluoride-ether complex is added. The amount of boron trifluoride-ether complex used is 0.05% of the weight of tetrabromobisphenol A. Keep the temperature and carry out the second reaction for 2 h;

[0055] After the second reaction is completed, a liquid caustic soda solution with a mass concentration of 50% is added. The amount of the liquid caustic soda solution used is 15% of the weight of tetrabromobisphenol A. Heat to 98 °C and carry out the third reaction for 2.5 h;

[0056] After the third reaction is completed, neutralize to pH = 7-8 with a phosphoric acid solution having a mass concentration of 30%, separate the liquid and filter to remove salts, and after removing the solvent, the brominated epoxy resin is obtained.

[0057] Example 4 Preparation of brominated epoxy resin: The amounts of raw materials and the preparation method are the same as those in Example 2. The difference from Example 2 is that the amount of boron trifluoride-ether complex is 0.8% of the weight of tetrabromobisphenol A.

[0058] Example 5 Preparation of brominated epoxy resin: The amounts of raw materials and the preparation method are the same as those in Example 2. The difference from Example 2 is that the amount of boron trifluoride-ether complex is 1% of the weight of tetrabromobisphenol A.

[0059] Example 6 Preparation of brominated epoxy resin: The amounts of raw materials, catalyst and various auxiliaries are the same as those in Example 2. The difference from Example 2 is that the liquid caustic soda solution is added in three times at 8%, 5% and 2%, and the reaction times for the three reactions are 1.5 h, 1 h and 0.5 h respectively.

[0060] Comparative Example 1 Preparation of brominated epoxy resin:

[0061] Epichlorohydrin, tetrabromobisphenol A and methyl isobutyl ketone solvent were mixed and dissolved according to a mass ratio of 1:0.3:0.35. A composite catalyst composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate in a weight ratio of 1:1 was added. The amount of the composite catalyst was 1.5% of the weight of tetrabromobisphenol A. It was heated to 70 °C and the first reaction was carried out for 2 h;

[0062] After the first reaction was completed, a liquid caustic soda solution with a mass concentration of 50% was added. The amount of the liquid caustic soda solution was 15% of the weight of tetrabromobisphenol A. It was heated to 98 °C and the second reaction was carried out for 2.5 h;

[0063] After the second reaction was completed, it was neutralized to pH = 7-8 with a phosphoric acid solution with a mass concentration of 30%. It was separated, filtered to remove salts, and the solvent was removed to obtain the brominated epoxy resin.

[0064] The difference from Example 2 is that boron trifluoride-ether complex was not added during the preparation of brominated epoxy resin in Comparative Example 1.

[0065] Comparative Example 2 Preparation of brominated epoxy resin:

[0066] Epichlorohydrin, tetrabromobisphenol A and methyl isobutyl ketone solvent were mixed and dissolved according to a mass ratio of 1:0.3:0.35. A composite catalyst composed of 1-butyl-3-methylimidazolium acetate and tetramethyl titanate in a weight ratio of 1:1 and boron trifluoride-ether complex were added. The amount of the composite catalyst was 1.5% of the weight of tetrabromobisphenol A, and the amount of boron trifluoride-ether complex was 0.05% of the weight of tetrabromobisphenol A. It was heated to 70 °C and the first reaction was carried out for 4 h;

[0067] After the first reaction is completed, a liquid caustic soda solution with a mass concentration of 50% is added. The dosage of the liquid caustic soda solution is 15% of the weight of tetrabromobisphenol A. It is heated to 98 °C and the second reaction is carried out for 2.5 h;

[0068] After the second reaction is completed, it is neutralized to pH = 7 - 8 with a phosphoric acid solution with a mass concentration of 30%. After liquid separation and filtration to remove salts, and after removing the solvent, the brominated epoxy resin is obtained.

[0069] The difference from Example 2 is that in the preparation of the brominated epoxy resin in Comparative Example 2, boron trifluoride-ether complex and the composite catalyst are added simultaneously.

[0070] Performance detection

[0071] The brominated epoxy resins prepared in Examples 1 - 6 and Comparative Example 1 are tested. The data of each index are recorded in Table 1 below. The molecular weight distribution index (PDI) is measured by a gel permeation chromatograph, which is the ratio of the weight-average molecular weight to the number-average molecular weight. The softening point is measured by the ring and ball method in GB / T 12007.6 - 1989 "Determination Method for Softening Point of Epoxy Resins", and the residual amount of tetrabromobisphenol A is measured by a high performance liquid chromatograph.

[0072] Table 1 Performance indicators of brominated epoxy resin

[0073] Group PDI Softening point / °C Residual amount of tetrabromobisphenol A / ppm Example 1 1.7 165 121 Example 2 1.4 180 86 Example 3 1.7 167 150 Example 4 1.2 188 101 Example 5 1.1 190 75 Example 6 1.4 185 Not detected Comparative Example 1 2.6 160 161 Comparative Example 2 3.7 145 481

[0074] It can be seen from the test results in Table 1 that the brominated epoxy resin obtained by the preparation method of the present application has excellent heat resistance, and has a narrow molecular weight distribution and no free bromine residue.

[0075] Compared with Example 2, boron trifluoride-ether complex was not added in the preparation process of Comparative Example 1, and the properties of the obtained brominated epoxy resin all decreased significantly, especially the molecular weight distribution, indicating that boron trifluoride-ether complex has an obvious positive promoting effect on the molecular weight distribution of brominated epoxy resin in the preparation process.

[0076] Compared with Example 2, in the preparation process of Comparative Example 2, boron trifluoride-ether complex and the composite catalyst were added to the reaction together, and the properties of the obtained brominated epoxy resin decreased significantly. This is because boron trifluoride-ether complex has strong acidity, which will affect the catalytic efficiency of the composite catalyst, resulting in a decrease in reaction selectivity. In addition, epichlorohydrin may undergo hydrolysis reaction under strong acidic conditions, further reducing the reaction selectivity and product purity.

[0077] Comparing the test results of Examples 2, 4, and 5, it can be seen that as the addition amount of boron trifluoride-ether complex increases, the test results get better and better. When the dosage of boron trifluoride-ether complex increases from 0.05% to 0.8% or 1%, the improvement effect of the performance of the prepared brominated epoxy resin is not much different. Considering the cost factor, the dosage of boron trifluoride-ether complex being 1% of the weight of tetrabromobisphenol A is the optimal dosage.

[0078] Preparation of brominated epoxy resin reinforced insulating board in Examples 7 - 14.

[0079] Among them, the raw materials: the curing agent uses dicyandiamide latent curing agent, the accelerator uses 2-phenylimidazole, the inorganic filler uses a combination of 10nm silica, 40nm silica, and 100nm silica, and the ratio of the three is 1:2:1. The organic flame retardant uses tris(2,6-dimethylphenyl)phosphine.

[0080] Preparation of brominated epoxy resin reinforced insulating board in Example 7:

[0081] Mix 100 parts of the brominated epoxy resin prepared in Example 1, 5 parts of nano-toughened epoxy resin, 5 parts of phenol-formaldehyde epoxy resin, 10 parts of curing agent, 0.1 part of accelerator, 30 parts of inorganic filler, 1 part of organic flame retardant, and 15 parts of dimethyl sulfoxide and stir evenly to obtain a glue solution;

[0082] Adopt a continuous method to impregnate NE fiberglass cloth with the glue solution, heat it in an oven at 150°C to volatilize the solvent, obtain a semi-cured film, cut it, stack the obtained 6 thin semi-cured films, and use a hot press for lamination. The heating rate is 2.5°C / min, the lamination temperature is 190°C, the lamination time is 1h, and the pressure is 25 kg / cm 2 , , and obtain a brominated epoxy resin reinforced insulating board.

[0083] Preparation of brominated epoxy resin reinforced insulating board in Example 8:

[0084] Mix 100 parts of the brominated epoxy resin prepared in Example 1, 7.5 parts of nano-toughened epoxy resin, 7.5 parts of phenol-formaldehyde epoxy resin, 20 parts of curing agent, 0.5 part of accelerator, 40 parts of inorganic filler, 2 parts of organic flame retardant, and 17 parts of dimethyl sulfoxide and stir evenly to obtain a glue solution;

[0085] Adopt a continuous method to impregnate NE fiberglass cloth with the glue solution, heat it in an oven at 150°C to volatilize the solvent, obtain a semi-cured film, cut it, stack the obtained 6 thin semi-cured films, and use a hot press for lamination. The heating rate is 2.5°C / min, the lamination temperature is 190°C, the lamination time is 1h, and the pressure is 25 kg / cm 2 ,, a brominated epoxy resin reinforced insulating board is obtained.

[0086] Preparation of the brominated epoxy resin reinforced insulating board in Example 9:

[0087] 100 parts of the brominated epoxy resin prepared in Example 1, 10 parts of nano toughened epoxy resin, 10 parts of phenol phenolic epoxy resin, 30 parts of curing agent, 1 part of accelerator, 50 parts of inorganic filler, 3 parts of organic flame retardant and 20 parts of dimethyl sulfoxide are mixed and stirred evenly to obtain a glue solution;

[0088] In a continuous manner, NE fiberglass cloth is impregnated with the glue solution, and the solvent is volatilized by heating in an oven at 150 °C to obtain a semi-cured film. The obtained 6 thin semi-cured films are stacked, cut, and pressed using a hot press. The heating rate is 2.5 °C / min, the pressing temperature is 190 °C, the pressing time is 1 h, and the pressure is 25 kg / cm 2 , , a brominated epoxy resin reinforced insulating board is obtained.

[0089] Preparation of the brominated epoxy resin reinforced insulating board in Example 10: The raw material dosage and preparation method are the same as those in Example 7. The difference from Example 7 is that the brominated epoxy resin prepared in Example 2 is used.

[0090] Preparation of the brominated epoxy resin reinforced insulating board in Example 11: The raw material dosage and preparation method are the same as those in Example 7. The difference from Example 7 is that the brominated epoxy resin prepared in Example 3 is used.

[0091] Preparation of the brominated epoxy resin reinforced insulating board in Example 12: The raw material dosage and preparation method are the same as those in Example 7. The difference from Example 7 is that the brominated epoxy resin prepared in Example 4 is used.

[0092] Preparation of the brominated epoxy resin reinforced insulating board in Example 13: The raw material dosage and preparation method are the same as those in Example 7. The difference from Example 7 is that the brominated epoxy resin prepared in Example 5 is used.

[0093] Preparation of the brominated epoxy resin reinforced insulating board in Example 14: The raw material dosage and preparation method are the same as those in Example 7. The difference from Example 7 is that the brominated epoxy resin prepared in Example 6 is used.

[0094] Performance testing

[0095] Performance tests are carried out on the insulating boards prepared in Examples 7 - 14 and the comparative example, and the test results are recorded in Table 2.

[0096] Tg: Glass transition temperature, which is measured according to the DSC test method specified in IPC-TM-650 2.4.25.

[0097] Damp heat resistance: Immerse the insulating board completely in water at 70 °C, and after soaking for 50 h and 80 h, detect the degradation degree of mechanical properties.

[0098] Coefficient of thermal expansion: Test according to IPC-TM-650 2.4.24 using a static thermal analyzer (TMA).

[0099] Peel strength: Determine according to IPC-TM-650 2.4.8.

[0100] Dielectric constant: Determine according to IPC-TM-650 2.5.5.13.

[0101] Flame retardancy: Test according to the test method of UL94 "50W (20mm) vertical burning test: V-0, V-1 and V-2".

[0102] Table 2 Test results

[0103]

[0104]

[0105] It can be seen from the test results in Table 2 that the insulating board prepared in this application has high peel strength, heat resistance and damp heat resistance, and at the same time has good dielectric properties and flame retardancy. Among them, the peel strength is greater than 0.6 N / mm, and the optimized formula and process can reach up to 0.91 N / mm at most; the dielectric constant < 3.7, the glass transition temperature reaches up to 210 °C at most, and the coefficient of thermal expansion < 28 ppm / °C.

[0106] The above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. Those skilled in the art, without departing from the spirit and scope of the present invention, when making some equivalent changes such as modifications and evolutions using the technical content disclosed above, are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A bromine-containing epoxy resin reinforced insulating board, characterized in that, It is formed by curing and pressing after the base material is infiltrated with the adhesive solution. The adhesive solution includes 100 parts of brominated epoxy resin, 5 - 10 parts of nano - toughened epoxy resin, 5 - 10 parts of phenol - phenolic epoxy resin, 10 - 30 parts of curing agent, 0.1 - 1 part of accelerator, 30 - 50 parts of inorganic filler, 1 - 3 parts of organic flame retardant, and 15 - 20 parts of dimethyl sulfoxide; the base material is selected from at least one of glass fiber felt, carbon fiber felt, Kevlar fiber felt, and aromatic polyamide paper fiber felt.

2. The bromine-containing epoxy resin reinforced insulating board according to claim 1, wherein, The preparation method of the brominated epoxy resin is as follows: Epichlorohydrin and tetrabromobisphenol A are added to the solvent, heated and dissolved, then a composite catalyst is added, and the reaction is carried out by heating for 1.5 - 2 h. Boron trifluoride - ethyl ether complex is added and the reaction continues for 1.5 - 2 h. After the reaction is completed, a liquid alkali solution is added, and the reaction is carried out by heating for 2 - 3 h. After the reaction is completed, an acid solution is added for neutralization and filtration to remove the solvent, thus obtaining the brominated epoxy resin.

3. The bromine-containing epoxy resin reinforced insulating board according to claim 2, characterized in that, The mass ratio of the tetrabromobisphenol A, epichlorohydrin, and solvent is 1:(0.2 - 0.4):(0.2 - 0.6).

4. The bromine-containing epoxy resin reinforced insulating board according to claim 3, characterized in that, The mass ratio of the tetrabromobisphenol A, epichlorohydrin, and solvent is 1:0.35:0.

5.

5. The bromine-containing epoxy resin reinforced insulating board according to claim 2, wherein The composite catalyst is composed of 1 - butyl - 3 - methylimidazolium acetate and tetramethyl titanate mixed in a mass ratio of 1:(0.8 - 1.2).

6. The bromine-containing epoxy resin reinforced insulating board according to claim 5, characterized in that, Based on the mass of tetrabromobisphenol A, the addition amount of the composite catalyst is 0.5 - 2 wt%.

7. The bromine-containing epoxy resin reinforced insulating board according to claim 6, wherein Based on the mass of tetrabromobisphenol A, the addition amount of the composite catalyst is 1.5 wt%.

8. The bromine-containing epoxy resin reinforced insulating board according to claim 2, wherein Based on the mass of tetrabromobisphenol A, the addition amount of the boron trifluoride - ethyl ether complex is 0.05 - 1 wt%.

9. The bromine-containing epoxy resin reinforced insulating board according to claim 8, wherein Based on the mass of tetrabromobisphenol A, the addition amount of the boron trifluoride - ethyl ether complex is 1 wt%.

10. A method for preparing a brominated epoxy resin-reinforced insulating board according to any one of claims 1-9, characterized in that, The specific steps are as follows: The base material is infiltrated with the adhesive solution, the solvent is volatilized by heating to obtain a semi - cured film, and multiple films are stacked and pressed to form the brominated epoxy resin - reinforced insulating board.

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