A bio-based epoxy resin precursor, a composite insulating material and a preparation method and application thereof

Abstract

The application discloses a kind of bio-based epoxy resin precursor, composite insulating material and its preparation method and application, belong to bio-based epoxy resin technical field, the bio-based epoxy resin precursor includes glycidyl ether structure and glycidyl ester structure, preparation method is as follows: (1) hydroxyl polyacid, allyl bromide occurs substitution reaction under the action of acid binding agent, and intermediate is prepared; (2) intermediate, hydrogen peroxide and acid catalyst are mixed and carried out oxidation reaction, and the bio-based epoxy resin precursor is prepared.The composite insulating material cured with the bio-based epoxy resin precursor has excellent thermodynamic performance and electrical performance, and also has the characteristics of rapid degradation under alkaline conditions and biodegradation in natural environment, suitable for the support, insulation and sealing of electrical equipment.

Description

Technical Field

[0001] This invention relates to the field of bio-based epoxy resin technology, specifically to a bio-based epoxy resin precursor, a composite insulating material, its preparation method, and its application. Background Technology

[0002] Epoxy resins possess good mechanical properties, high-temperature resistance, and excellent insulation properties, leading to their wide application in many fields, such as adhesives, electronic instruments, light industry, construction, machinery, aerospace, coatings, and electrical and electronic insulation materials. Currently, the most widely used electrical epoxy resin is bisphenol A diglycidyl ether (DGEBA), accounting for over 90% of the epoxy resin market. However, DGEBA's raw materials are almost entirely derived from petrochemicals, and it contains bisphenol A structural units, which can potentially impact the environment and human health. Against this backdrop, the environmental friendliness of epoxy resins is receiving increasing attention.

[0003] From the perspective of raw material sources, developing high-performance bio-based epoxy resins using natural renewable resources as raw materials to partially replace existing petroleum-based epoxy resins is one of the effective ways to achieve environmental protection of epoxy resins. This not only effectively reduces the consumption of petrochemical resources but also benefits environmental protection. For example, Liu Hechen et al. from North China Electric Power University developed a new type of environmentally friendly insulating material using itaconic acid epoxy resin as raw material, but its related electrical properties are weaker than those of DGEBA type epoxy resin (Journal of Electrical Engineering, 2022, 37(09): 2366-2376).

[0004] Chinese patent document CN115449054A discloses a bio-based epoxy resin based on paeonol. The invention uses paeonol as a raw material and prepares bio-based bisphenols through simple demethylation. The bisphenols are then glycidized at both ends to obtain bio-based epoxy resin monomers based on paeonol. However, the invention does not include any research on the electrical properties of the bio-based epoxy resin monomers based on paeonol.

[0005] Chinese patent document CN114395216A discloses a bio-based hyperbranched polymer epoxy resin, which is obtained by dynamic crosslinking of ferulic acid hyperbranched epoxy resin and citric acid hyperbranched polyester. The crosslinked network structure forms numerous interfacial covalent bonds, giving the epoxy resin the ability to be reprocessed. Under the action of sodium hydroxide aqueous solution, it can be controlled to degrade into ferulic acid and citric acid hyperbranched polyester. The degradation products, ferulic acid and citric acid hyperbranched polyester, can be reprocessed to prepare a fully bio-based epoxy resin, achieving green closed-loop recycling of epoxy resin. Although this bio-based hyperbranched polymer epoxy resin can be applied in fields such as electronic packaging, insulating materials, and printed circuit boards, its structure is relatively complex, and its preparation method is also complex and cumbersome. Summary of the Invention

[0006] This invention provides a bio-based epoxy resin precursor comprising glycidyl ether and glycidyl ester structures. The preparation method is simple and the reaction conditions are controllable. Using this bio-based epoxy resin precursor, a biodegradable composite insulating material curing product with excellent thermodynamic and electrical properties can be further prepared.

[0007] The specific technical solution adopted is as follows:

[0008] A bio-based epoxy resin precursor having any one of the structures shown in formulas (I)-(III):

[0009]

[0010] This invention also provides a method for preparing the aforementioned bio-based epoxy resin precursor, specifically comprising the following steps:

[0011] (1) A hydroxypolyacid and allyl bromide undergo a substitution reaction under the action of an acid-binding agent to prepare an intermediate, wherein the intermediate has any one of the structures shown in formulas (Ⅳ)-(Ⅵ):

[0012]

[0013] (2) The intermediate obtained in step (1), hydrogen peroxide and acid catalyst are mixed and subjected to oxidation reaction to prepare the bio-based epoxy resin precursor.

[0014] This invention utilizes hydroxy polyacids as raw materials to develop a series of multifunctional bio-based epoxy resin precursors. These precursors contain both glycidyl ether and glycidyl ester structures. Combining the glycidyl ether and glycidyl ester structures yields a series of epoxy resin systems with excellent thermodynamic, electrical, and degradation properties. Furthermore, the preparation method for these bio-based epoxy resin precursors is simple, the reaction conditions are controllable, and the process is easy to implement, making it suitable for large-scale industrial production.

[0015] Preferably, the hydroxypolyacid includes at least one of malic acid, tartaric acid, and mucilage.

[0016] Preferably, the acid-binding agent includes at least one of triethylamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, and potassium carbonate.

[0017] Preferably, the acidic catalyst includes at least one of acetic acid, phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, and solid acid, wherein the solid acid includes, but is not limited to, trichloroacetic acid, periodic acid, dinitrobenzoic acid, ethylenediaminetetraacetic acid, etc.

[0018] Preferably, in step (1), the molar ratio of hydroxy polyacid, allyl bromide and acid-binding agent is 1:3 to 8:3 to 8; the preferred reaction conditions are 60 to 80°C and 6 to 24 hours.

[0019] Preferably, in step (2), the molar ratio of the intermediate, hydrogen peroxide and acid catalyst is 1:3 to 8:0.1 to 0.3; the preferred reaction conditions are 40 to 100°C and 12 to 24 hours.

[0020] The present invention also provides a composite insulating material composition comprising the aforementioned bio-based epoxy resin precursor.

[0021] Preferably, the composite insulating material composition further includes an epoxy diluent, a curing agent, an accelerator, and an inorganic filler; more preferably, the mass ratio of the bio-based epoxy resin precursor, epoxy diluent, curing agent, accelerator, and inorganic filler is 1:0.1-0.2:0.6-1.0:0.001-0.006:0.5-0.8.

[0022] Preferably, the epoxy diluent includes at least one of butyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, C12-14 fatty glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether.

[0023] Preferably, the curing agent is an acid anhydride curing agent, which includes, but is not limited to, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, high phthalic anhydride, biphenyl anhydride, phenylmaleic anhydride, trimellitic anhydride, phthalic anhydride, phenylsuccinic anhydride, pyromellitic dianhydride, 1,8-naphthalic anhydride, 1,2-naphthalic anhydride, 2,3-pyrazinic anhydride, 3-hydroxyphthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, or 2,3-pyridinedicarboxylic anhydride.

[0024] Preferably, the promoter includes at least one of tertiary amines, tertiary amine salts, quaternary ammonium salts, imidazole compounds, organophosphorus compounds, metal acetylacetone salts, metal carboxylic acid salts, and boron trifluoride amine complexes.

[0025] Preferably, the inorganic filler includes at least one of talc, wollastonite, microsilica, barium sulfate, and aluminum hydroxide.

[0026] This invention also provides a cured composite insulating material, obtained by curing the aforementioned composite insulating material composition at 80–150°C. This cured composite insulating material maintains excellent thermodynamic and electrical properties while also exhibiting good degradation resistance, making it suitable for supporting, insulating, and sealing electrical equipment.

[0027] Specifically, the bio-based epoxy resin precursor, epoxy diluent, curing agent, accelerator and inorganic filler are stirred and mixed in a temperature range of 80 to 100°C, and then the resulting mixture is cured in a temperature range of 80 to 150°C to obtain the cured composite insulation material.

[0028] Preferably, the glass transition temperature of the cured composite insulating material is 60-140℃, the tensile strength is 60-80MPa, the thermal conductivity is ≥0.5, and the electrical strength is ≥30KV / mm; it has the characteristics of rapid degradation under alkaline conditions and biodegradation in the natural environment.

[0029] The present invention also provides the application of the aforementioned composite insulating material composition or the cured composite insulating material in the field of power equipment.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) The present invention uses bio-based hydroxy polyacids as raw materials to develop a series of multifunctional bio-based epoxy resin precursors. The bio-based epoxy resin precursors have both glycidyl ether structure and glycidyl ester structure. The preparation method is simple, the reaction conditions are controllable, it is easy to implement, and it is suitable for large-scale industrial production.

[0032] (2) The composite insulating material cured by using the bio-based epoxy resin precursor has excellent thermodynamic and electrical properties, as well as the characteristics of rapid degradation under alkaline conditions and biodegradation in the natural environment, making it suitable for the support, insulation and sealing of power equipment. Attached Figure Description

[0033] Figure 1 The image shows the infrared spectrum of the bio-based epoxy resin precursor synthesized in Example 1.

[0034] Figure 2 The image shows the infrared spectrum of the bio-based epoxy resin precursor synthesized in Example 2.

[0035] Figure 3 The image shows the infrared spectrum of the bio-based epoxy resin precursor synthesized in Example 3.

[0036] Figure 4 The graph shows the thermal conductivity of the cured composite insulating materials in Examples 1-3. Detailed Implementation

[0037] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0038] Unless otherwise specified, all experimental materials used in the examples can be purchased from conventional biochemical reagent companies.

[0039] Example 1

[0040] (1) On a molar basis, 1 part of malic acid and 5 parts of allyl bromide were subjected to a substitution reaction in the presence of 3 parts of triethylamine. The reaction was carried out at 60°C for 24 hours to obtain intermediate 1.

[0041] (2) In the presence of 0.1 parts acetic acid, 1 part intermediate 1 and 6 parts hydrogen peroxide were reacted at 40°C for 24 hours to obtain a bio-based epoxy resin precursor with the structural formula shown in formula (I); the infrared test results of the bio-based epoxy resin precursor are as follows: Figure 1 As shown, this demonstrates the successful synthesis of the bio-based epoxy resin precursor.

[0042]

[0043] (3) The bio-based epoxy resin precursor, butyl glycidyl ether, curing agent methyl hexahydrophthalic anhydride, accelerator zinc acetylacetonate and microsilica powder shown in formula (Ⅰ) are mixed in a mass ratio of 1:0.1:0.75:0.001:0.8 and then pre-cured. Finally, the mixture is post-cured in a vacuum oven at 130°C for 4 hours to obtain the cured composite insulation material.

[0044] The composite insulating material cured in this embodiment has a glass transition temperature of 65°C, a tensile strength of 60 MPa, and a thermal conductivity of 0.53 (at 25°C; the thermal conductivity changes with temperature as follows). Figure 4 As shown in the figure, the electrical strength is 31 kV / mm. The cured composite insulation material completely degrades in a 0.5 mol / L sodium hydroxide tetrahydrofuran-water (1:1) solution at 50°C for 50 h.

[0045] Example 2

[0046] (1) On a molar basis, 1 part tartaric acid and 8 parts allyl bromide were subjected to a substitution reaction in the presence of 4 parts pyridine. The reaction was carried out at 80°C for 6 hours to obtain intermediate 2.

[0047] (2) In the presence of 0.2 parts hydrochloric acid, 1 part intermediate 2 and 6 parts hydrogen peroxide were reacted at 80°C for 14 hours to obtain a bio-based epoxy resin precursor with the structural formula shown in formula (II); the infrared test results of the bio-based epoxy resin precursor are as follows: Figure 2 As shown, this demonstrates the successful synthesis of the bio-based epoxy resin precursor.

[0048]

[0049] (3) The bio-based epoxy resin precursor shown in formula (II), neopentyl glycol diglycidyl ether, curing agent methyltetrahydrophthalic anhydride, accelerator triethanolamine and aluminum hydroxide are mixed in a mass ratio of 1:0.1:1:0.005:0.6, pre-cured, and finally post-cured in a vacuum oven at 150°C for 4 hours to obtain the composite insulation material cured product.

[0050] The composite insulating material cured in this embodiment has a glass transition temperature of 100℃, a tensile strength of 74MPa, and a thermal conductivity of 0.61 (at 25℃; the thermal conductivity changes with temperature as follows). Figure 4 As shown in the figure, the electrical strength is 33 kV / mm. The cured composite insulation material completely degrades in a 0.5 mol / L sodium hydroxide DMF-water (1:1) solution at 80°C for 36 hours.

[0051] Example 3

[0052] (1) In molar amounts, 1 part of viscous acid and 8 parts of allyl bromide were subjected to a substitution reaction in the presence of 6 parts of N,N-diisopropylethylamine. The reaction was carried out at 80°C for 12 hours to obtain intermediate 3.

[0053] (2) In the presence of 0.2 parts sulfuric acid, 1 part intermediate 3 and 8 parts hydrogen peroxide were reacted at 100°C for 12 hours to obtain a bio-based epoxy resin precursor with the structural formula shown in formula (Ⅲ); the infrared test results of the bio-based epoxy resin precursor are as follows: Figure 3 As shown, this demonstrates the successful synthesis of the bio-based epoxy resin precursor.

[0054]

[0055] (3) The bio-based epoxy resin precursor, benzyl glycidyl ether, curing agent trimellitic anhydride, accelerator boron trifluoride diethyl ether complex and microsilica powder shown in formula (Ⅲ) are mixed in a mass ratio of 1:0.2:0.8:0.006:0.8 and then pre-cured. Finally, the mixture is post-cured in a vacuum oven at 150°C for 10 hours to obtain the cured composite insulation material.

[0056] The composite insulating material cured product obtained in this embodiment has a glass transition temperature of 122℃, a tensile strength of 78MPa, and a thermal conductivity of 0.62 (at 25℃, the thermal conductivity changes with temperature as follows). Figure 4 As shown in the figure, the electrical strength is 35 kV / mm. The cured composite insulation material completely degrades in a 1 mol / L sodium hydroxide DMF-water (1:1) solution at 80°C for 24 hours.

[0057] Example 4

[0058] The bio-based epoxy resin precursor shown in formula (Ⅰ), 1,6-hexanediol diglycidyl ether, curing agent 2,3-pyridine dicarboxylic anhydride, accelerator hexadecyl dimethyl benzyl ammonium and wollastonite were mixed in a mass ratio of 1:0.1:1:0.0045:0.8 and then pre-cured. Finally, the mixture was post-cured in a vacuum oven at 120°C for 14 hours to obtain the cured composite insulation material.

[0059] The cured composite insulating material prepared in this embodiment has a glass transition temperature of 90℃, a tensile strength of 67MPa, a thermal conductivity of 0.78, and an electrical strength of 36KV / mm. The cured composite insulating material completely degrades in a 0.5mol / L sodium hydroxide-DMSO-water (1:1) solution at 80℃ for 80 hours.

[0060] Example 5

[0061] The bio-based epoxy resin precursor shown in formula (II), 1,4-butanediol diglycidyl ether, curing agent 2,3-naphthalenedicarboxylic anhydride, accelerator hexadecyl dimethyl benzyl ammonium, and microsilica powder were mixed in a mass ratio of 1:0.15:0.75:0.001:0.8, pre-cured, and finally post-cured in a vacuum oven at 130°C for 8 hours to obtain the cured composite insulating material.

[0062] The cured composite insulating material prepared in this embodiment has a glass transition temperature of 118℃, a tensile strength of 80MPa, a thermal conductivity of 0.59, and an electrical strength of 41KV / mm. This cured composite insulating material completely degrades in a 1mol / L sodium hydroxide-DMAC-water (1:1) solution at 80℃ for 40 hours.

[0063] Example 6

[0064] The bio-based epoxy resin precursor shown in formula (Ⅲ), polypropylene glycol diglycidyl ether, curing agent pyromellitic dianhydride, accelerator boron trifluoride ethylamine, and barium sulfate were mixed in a mass ratio of 1:0.2:1:0.006:0.7, pre-cured, and finally post-cured in a vacuum oven at 150°C for 15 hours to obtain the cured composite insulation material.

[0065] The composite insulating material cured in this embodiment has a glass transition temperature of 126℃, a tensile strength of 78MPa, a thermal conductivity of 0.73, and an electrical strength of 43KV / mm. This DMAC was completely degraded in a 0.3mol / L sodium hydroxide-DMF-water (1:1) solution at 50℃ for 100h.

[0066] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a composite insulating material composition in the field of power equipment, characterized in that, The components of the composite insulating material composition include a bio-based epoxy resin precursor, an epoxy diluent, a curing agent, an accelerator, and an inorganic filler. The mass ratio of the bio-based epoxy resin precursor, epoxy diluent, curing agent, accelerator, and inorganic filler is 1:0.1~0.2:0.6~1.0:0.001~0.006:0.5~0.8; The bio-based epoxy resin precursor has the structure shown in formula (Ⅲ): ； （Ⅲ）； The method for preparing the bio-based epoxy resin precursor includes the following steps: (1) A hydroxypolyacid and allyl bromide undergo a substitution reaction under the action of an acid-binding agent to prepare an intermediate having the structure shown in formula (VI): ； （Ⅵ）； (2) The intermediate obtained in step (1), hydrogen peroxide and acidic catalyst are mixed and subjected to oxidation reaction to prepare the bio-based epoxy resin precursor; the acidic catalyst is sulfuric acid.

2. The application according to claim 1, characterized in that, The hydroxy polyacid mentioned is a viscous acid; And / or, the acid-binding agent includes at least one of triethylamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, and potassium carbonate.

3. The application according to claim 1, characterized in that, In step (1), the molar ratio of hydroxy polyacid, allyl bromide and acid-binding agent is 1:3~8:3~8; and / or, in step (2), the molar ratio of intermediate, hydrogen peroxide and acid catalyst is 1:3~8:0.1~0.

3.

4. The application according to claim 1, characterized in that, In step (1), the reaction conditions are 60~80 ℃ for 6~24 h; and / or, in step (2), the reaction conditions are 40~100 ℃ for 12~24 h.

5. The application according to claim 1, characterized in that, The epoxy diluent includes at least one of butyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, C12-14 fatty glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether. And / or, the curing agent is an acid anhydride curing agent; And / or, the promoter includes at least one of tertiary amines, tertiary amine salts, quaternary ammonium salts, imidazole compounds, organophosphorus compounds, metal salts of acetylacetone, metal salts of carboxylic acids, and boron trifluoride amine complexes; And / or, the inorganic filler includes at least one of talc, wollastonite, microsilica, barium sulfate, and aluminum hydroxide.

6. The application of cured composite insulating materials in the field of power equipment, characterized in that, The cured composite insulating material is obtained by curing the composite insulating material composition of claim 1 at 80~150 ℃. The glass transition temperature of the cured composite insulating material is 60~140 ℃, the tensile strength is 60~80 MPa, the thermal conductivity is ≥0.5, and the electrical strength is ≥30 KV / mm.

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