Biomass flame-retardant epoxy electronic packaging material and preparation method thereof

Abstract

The invention discloses a biomass flame-retardant epoxy electronic packaging material and a preparation method thereof.The biomass flame-retardant epoxy electronic packaging material is prepared from epoxy resin and a flame-retardant curing agent, the chemical formula of the flame-retardant curing agent is C32H24B2N4O4, the structural formula of the flame-retardant curing agent is # imgabs0 #, the flame-retardant curing agent contains a benzimidazole-like structure, so that the thermal stability and the char forming amount of the flame-retardant curing agent are improved, and the flame-retardant curing agent does not contain phosphorus or halogen and is environmentally friendly. And only environment-friendly flame-retardant elements nitrogen and boron are contained. And the existence of boron and nitrogen elements has good flame retardant efficiency improvement and smoke suppression performance. Meanwhile, the flame retardant contains active amino groups and can be used for epoxy curing.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant epoxy materials, and in particular relates to a biomass flame retardant epoxy electronic packaging material and a preparation method thereof. Background Art

[0002] As one of the three major thermosetting resins, epoxy resin is widely used in coatings, adhesives, composite materials, electronic packaging and printed circuit boards due to its excellent solubility resistance, dimensional stability, excellent adhesion, electrical insulation and good mechanical properties. However, the oxygen index of traditional epoxy resin is about 19.8%, showing strong flammability, which greatly limits its application areas. Therefore, it is very necessary to improve the flame retardant properties of epoxy resin.

[0003] At present, the main method to improve the flame retardant properties of epoxy resin is by introducing flame retardants. According to the introduction method of flame retardants, they can be divided into additive type and reactive type. Additive flame retardants disperse flame retardants in epoxy matrix by physical blending. Although there are many types, they often have problems such as poor compatibility with epoxy matrix and low flame retardant efficiency. Reactive flame retardants contain groups that can participate in epoxy curing, such as amino, epoxy and hydroxyl groups. Flame retardants are introduced into epoxy polymer chains by co-curing, which usually have better compatibility and higher flame retardant efficiency.

[0004] With the implementation of a series of environmental regulations, halogen flame retardants are restricted because they produce a lot of harmful gases when burning. Organophosphorus flame retardants have therefore received more and more attention, but they also have their own shortcomings, such as being volatile and producing a lot of smoke when burning, which may increase the risk of fire.

[0005] With the continuous improvement of environmental awareness and requirements, halogen-free and phosphorus-free flame retardants are increasingly favored by researchers. Polybenzimidazole exhibits good thermal stability and flame retardancy because it contains a benzimidazole structure with excellent thermal stability. Inspired by this, researchers introduced the benzimidazole structure into the epoxy resin system. However, the introduction of only the benzimidazole structure is effective in improving the flame retardant properties of epoxy resin, and it usually needs to be used in combination with phosphorus-containing flame retardants. Boron-based flame retardants have attracted attention due to their low toxicity, abundant resources and excellent flame retardant effects. Organic boron flame retardants can generate glass-like viscous substances when thermally decomposed, which plays a condensed phase flame retardant role and reduces smoke toxicity.

[0006] At the same time, due to the unsustainability of petrochemical resources, the application of biomass raw materials in the polymer field is becoming increasingly popular. In the field of flame retardancy, biomass-based green flame retardant curing agents have also been the goal of the industry. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a biomass flame retardant epoxy electronic packaging material.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned biomass flame retardant epoxy electronic packaging material.

[0009] Another object of the present invention is to provide a flame retardant curing agent for epoxy resin.

[0010] Another object of the present invention is to provide a method for preparing the flame retardant curing agent.

[0011] The technical solution of the present invention is as follows:

[0012] A biomass flame retardant epoxy electronic packaging material, the raw materials of which include epoxy resin and flame retardant curing agent, the chemical formula of which is C 32 H 24 B 2 N 4 O 4 , the structural formula is

[0013] In a preferred embodiment of the present invention, the epoxy resin is epoxy resin E51.

[0014] In a preferred embodiment of the present invention, the chemical molar ratio of the epoxy groups in the epoxy resin to the hydrogen on the amino group of the flame retardant curing agent is equal.

[0015] The method for preparing the biomass flame retardant epoxy electronic packaging material comprises: mixing the flame retardant curing agent with the epoxy resin monomer, degassing the mixture, and then performing a curing reaction.

[0016] In a preferred embodiment of the present invention, the curing reaction procedure is: keep the reaction at 90-110°C for 1-3 hours, then keep the reaction at 140-160°C for 1-3 hours, and then keep the reaction at 170-190°C for 0.5-2 hours.

[0017] A flame retardant curing agent for epoxy resin, having the chemical formula C 32 H 24 B 2 N 4 O 4 , the structural formula is

[0018]

[0019] The preparation method of the flame retardant curing agent comprises the following steps:

[0020] (1) In an air atmosphere, 3,4-dihydroxybenzaldehyde and ammonium acetate are added to a flask equipped with a mechanical stirring device and a condenser, and dissolved with ethyl acetate. The mixture is heated to 60-70°C for reaction for 0.5-2h, then o-phenylenediamine is added, and the reaction is continued for 3-8h at a temperature of 100-200°C. The temperature is then cooled to room temperature, and the ethyl acetate is removed. Deionized water is added for ultrasonic treatment, and then the mixture is washed and vacuum dried to obtain a white solid powder.

[0021] (2) The white solid powder obtained in step (1) is fully dissolved in tetrahydrofuran, 3-aminophenylboric acid and deionized water are added, and anhydrous magnesium sulfate is added after stirring. The mixture is reacted at room temperature for 24 to 36 hours, and then solid-liquid separation is performed to obtain a solid. The solid is then fully dissolved in n-heptane, and the filtrate is filtered, evaporated and concentrated, and vacuum dried to obtain the flame retardant curing agent.

[0022] In a preferred embodiment of the present invention, in step (1), the ratio of 3,4-dihydroxybenzaldehyde, ethyl acetate, ammonium acetate and o-phenylenediamine is 13-30 g:100 mL:0.4-4 g:10-11 g.

[0023] In a preferred embodiment of the present invention, in step (2), the ratio of white solid powder, tetrahydrofuran, 3-aminophenylboric acid and anhydrous magnesium sulfate is 13-18 g: 150 mL: 13-14 g: 20-30 g.

[0024] In a preferred embodiment of the present invention, in the step (1), the ratio of 3,4-dihydroxybenzaldehyde, ethyl acetate, ammonium acetate and o-phenylenediamine is 13-30 g:100 mL:0.4-4 g:10-11 g; in the step (2), the ratio of white solid powder, tetrahydrofuran, 3-aminophenylboric acid and anhydrous magnesium sulfate is 13-18 g:150 mL:13-14 g:20-30 g.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention introduces a benzimidazole-like structure into the flame retardant curing agent through reasonable molecular design, which is beneficial to improving the thermal stability and carbonization amount of the flame retardant.

[0027] 2. The flame retardant curing agent in the present invention does not contain phosphorus or halogen, and the flame retardant is green and environmentally friendly. The boron element contained in the flame retardant can exhibit the effect of condensed phase flame retardancy, and cooperates with the high carbon residue benzimidazole structure to exhibit good smoke suppression effect and low toxicity.

[0028] 3. The flame retardant curing agent in the present invention uses 3,4-dihydroxybenzaldehyde as a biomass raw material, which is green, environmentally friendly and sustainable.

[0029] 4. The flame retardant curing agent in the present invention can be used as a curing agent for epoxy monomers. It is a reactive flame retardant, which avoids migration failure and the problem of poor compatibility with the matrix affecting the mechanical properties of the epoxy matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the H NMR spectrum of the white powder obtained in Example 1 of the present invention.

[0031] Figure 2 This is the infrared spectrum of the target flame retardant curing agent obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further illustrated and described below through specific implementation modes in combination with the accompanying drawings.

[0033] Example 1

[0034] Under air atmosphere, 13.8 g of 3,4-dihydroxybenzaldehyde, 100 mL of ethyl acetate and 0.4 g of ammonium acetate were added to a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, and the mixture was heated to 70°C for reaction for 0.5 h. After the reaction, 10.82 g of o-phenylenediamine was added to the system and the reaction was continued at 70°C for 3 h. After the reaction, the ethyl acetate solvent was removed by rotary evaporation, deionized water was added to the crude product and ultrasonicated for 0.5 h, centrifuged and washed with ethanol, and the product was placed in a 60°C oven for vacuum drying for 12 h to obtain the following Figure 1 The white solid powder is shown.

[0035] Dissolve 17.4 g of white powder in 150 mL of tetrahydrofuran, ultrasonically stir until it is completely dissolved, then add 13.7 g of 3-aminophenylboronic acid, then add 1 g of deionized water, stir for 5 to 10 min, then add 24 g of anhydrous magnesium sulfate, react at room temperature for 24 h, filter after the reaction, evaporate and concentrate the filtrate to obtain a solid, then fully dissolve in n-heptane, filter, evaporate and concentrate the filtrate to obtain the product, and finally dry in a vacuum oven at 50 ° C for 24 h to obtain the following: Figure 2 The target flame retardant curing agent shown has the structural formula

[0036] Example 2

[0037] Under air atmosphere, 27.6 g of 3,4-dihydroxybenzaldehyde, 100 mL of ethyl acetate and 0.4 g of ammonium acetate were added to a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, and the mixture was heated to 70°C for reaction for 0.5 h. After the reaction, 10.82 g of o-phenylenediamine was added to the system and the reaction was continued at 70°C for 3 h. After the reaction, the ethyl acetate solvent was removed by rotary evaporation, deionized water was added to the crude product and ultrasonicated for 0.5 h, centrifuged and washed with ethanol, and the product was placed in a 60°C oven for vacuum drying for 12 h to obtain a white solid powder.

[0038] 17.4 g of white powder was dissolved in 150 mL of tetrahydrofuran, and ultrasonically stirred until it was completely dissolved. Then 13.7 g of 3-aminophenylboronic acid was added, and then 1 g of deionized water was added, and stirred for 5 to 10 min. Then 24 g of anhydrous magnesium sulfate was added, and the mixture was reacted at room temperature for 24 h. After the reaction was completed, the mixture was filtered, and the filtrate was evaporated and concentrated to obtain a solid. The solid was then fully dissolved in n-heptane, filtered, and the filtrate was evaporated and concentrated to obtain a product. Finally, the product was dried in a vacuum oven at 50° C. for 24 h to obtain the target flame retardant curing agent, whose structural formula is the same as that of Example 1.

[0039] Example 3

[0040] Under air atmosphere, 13.8 g of 3,4-dihydroxybenzaldehyde, 100 mL of ethyl acetate and 4 g of ammonium acetate were added to a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, and the mixture was heated to 70°C for reaction for 0.5 h. After the reaction, 10.82 g of o-phenylenediamine was added to the system and the reaction was continued at 70°C for 3 h. After the reaction, the ethyl acetate solvent was removed by rotary evaporation, deionized water was added to the crude product and ultrasonicated for 0.5 h, centrifuged and washed with ethanol, and the product was placed in a 60°C oven for vacuum drying for 12 h to obtain a white solid powder.

[0041] Dissolve 17.4 g of white powder in 150 mL of tetrahydrofuran, ultrasonically stir until it is completely dissolved, then add 13.7 g of 3-aminophenylboronic acid, then add 1 g of deionized water, stir for 5 to 10 min, then add 24 g of anhydrous magnesium sulfate, react at room temperature for 24 h, filter after the reaction, evaporate and concentrate the filtrate to obtain a solid, then fully dissolve it in n-heptane, filter, evaporate and concentrate the filtrate to obtain the product, and finally dry it in a vacuum oven at 50 ° C for 24 h to obtain the target flame retardant curing agent.

[0042] Example 4

[0043] Under air atmosphere, 13.8 g of 3,4-dihydroxybenzaldehyde, 100 mL of ethyl acetate and 0.4 g of ammonium acetate were added to a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, and the mixture was heated to 70°C for reaction for 0.5 h. After the reaction, 10.82 g of o-phenylenediamine was added to the system and the reaction was continued at 70°C for 3 h. After the reaction, the ethyl acetate solvent was removed by rotary evaporation, deionized water was added to the crude product and ultrasonicated for 0.5 h, centrifuged and washed with ethanol, and the product was placed in a 60°C oven for vacuum drying for 12 h to obtain a white solid powder.

[0044] Dissolve 13.7 g of white powder in 150 mL of tetrahydrofuran, ultrasonically stir until it is completely dissolved, then add 13.7 g of 3-aminophenylboronic acid, then add 1 g of deionized water, stir for 5 to 10 minutes, then add 24 g of anhydrous magnesium sulfate, react at room temperature for 24 hours, filter after the reaction, evaporate and concentrate the filtrate to obtain a solid, then fully dissolve it in n-heptane, filter, evaporate and concentrate the filtrate to obtain the product, and finally dry it in a vacuum oven at 50°C for 24 hours to obtain the target flame retardant curing agent.

[0045] Example 5 Flame retardant performance test

[0046] The target flame retardant curing agent prepared in Example 1 was added to the epoxy resin E51 according to the chemical molar ratio of epoxy group to hydrogen on the flame retardant amino group, heated to 70°C, degassed for 10 minutes, and poured into a mold preheated at 100°C. The mixture was kept at 100°C for 2 hours, then at 150°C for 2 hours, and at 180°C for 1 hour to obtain flame retardant modified bars. A comparative bar was obtained using 4,4'-diaminodiphenylmethane as a curing agent under the same curing conditions.

[0047] In this embodiment, the flame retardant performance of the material was tested according to GB / T 2408-2008 standard, and the thermal stability of the material at high temperature was analyzed using a thermogravimetric analyzer. The results are shown in Table 1.

[0048] Table 1 Test results of flame retardant properties and high temperature thermal stability of the test specimens

[0049] Oxygen Index LOI UL-94 700℃ carbon residue rate Comparison sample 24.5％ NR 15.3％ Flame retardant modified sample 31.2％ V-0 24.6％

[0050] The above results show that compared with traditional curing agents, selecting biomass boron-nitrogen curing agent as the curing agent for epoxy monomer has a significant effect on improving the flame retardant properties of epoxy resin.

[0051] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A biomass flame retardant epoxy electronic packaging material, characterized in that: The raw materials include epoxy resin and flame retardant curing agent, the chemical formula of which is C 32 H 24 B2N4O4, the structural formula is 2. The biomass flame retardant epoxy electronic packaging material according to claim 1, characterized in that: The epoxy resin is epoxy resin E51.

3. A biomass flame retardant epoxy electronic packaging material as claimed in claim 1 or 2, characterized in that: The epoxy groups in the epoxy resin and the hydrogen on the amino group of the flame retardant curing agent have the same chemical molar ratio.

4. The method for preparing a biomass flame retardant epoxy electronic packaging material according to any one of claims 1 to 3, characterized in that: include: The flame retardant curing agent is mixed with the epoxy resin monomer and degassed before curing reaction.

5. The preparation method according to claim 4, characterized in that: The procedure of the curing reaction is: keep the reaction at 90-110° C. for 1-3 hours, then keep the reaction at 140-160° C. for 1-3 hours, and then keep the reaction at 170-190° C. for 0.5-2 hours.

6. A flame retardant curing agent for epoxy resin, characterized in that: Its chemical formula C 32 H 24 B2N4O4, the structural formula is 7. The method for preparing the flame retardant curing agent according to claim 6, characterized in that: The steps include: (1) In an air atmosphere, 3,4-dihydroxybenzaldehyde and ammonium acetate are added to a flask equipped with a mechanical stirring device and a condenser, and dissolved with ethyl acetate. The mixture is heated to 60-70°C for reaction for 0.5-2h, then o-phenylenediamine is added, and the reaction is continued for 3-8h at a temperature of 100-200°C. The temperature is then cooled to room temperature, and the ethyl acetate is removed. Deionized water is added for ultrasonic treatment, and then the mixture is washed and vacuum dried to obtain a white solid powder. (2) The white solid powder obtained in step (1) is fully dissolved in tetrahydrofuran, 3-aminophenylboric acid and deionized water are added, and anhydrous magnesium sulfate is added after stirring. The mixture is reacted at room temperature for 24 to 36 hours, and then solid-liquid separation is performed to obtain a solid. The solid is then fully dissolved in n-heptane, and the filtrate is filtered, evaporated and concentrated, and vacuum dried to obtain the flame retardant curing agent.

8. The preparation method according to claim 7, characterized in that: In the step (1), the ratio of 3,4-dihydroxybenzaldehyde, ethyl acetate, ammonium acetate and o-phenylenediamine is 13-30 g:100 mL:0.4-4 g:10-11 g.

9. The preparation method according to claim 7, characterized in that: In the step (2), the ratio of the white solid powder, tetrahydrofuran, 3-aminophenylboric acid and anhydrous magnesium sulfate is 13-18 g: 150 mL: 13-14 g: 20-30 g.

10. The preparation method according to claim 7, characterized in that: In the step (1), the ratio of 3,4-dihydroxybenzaldehyde, ethyl acetate, ammonium acetate and o-phenylenediamine is 13-30 g:100 mL:0.4-4 g:10-11 g; in the step (2), the ratio of white solid powder, tetrahydrofuran, 3-aminophenylboric acid and anhydrous magnesium sulfate is 13-18 g:150 mL:13-14 g:20-30 g.

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