Fireproof composite material and preparation method thereof

Abstract

The invention discloses a fireproof composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The fireproof composite material comprises the following raw materials in parts by weight: 60-80 parts of epoxy resin, 20-30 parts of silicon dioxide, 10-18 parts of a flame retardant, 10-15 parts of a curing agent, 2-5 parts of a toughening agent, 1-2 parts of an accelerant and 1-3 parts of an antioxidant. The toughening agent is prepared by reacting trimesic acid with oleyl alcohol to generate a triester compound, reacting 1, 4-benzene diboric acid with 3-sulfydryl-1, 2-propylene glycol to generate a dioxaboroheterocyclic compound, and reacting the triester compound with the dioxaboroheterocyclic compound. The fireproof composite material prepared by the invention has good flame retardant property and impact resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a fireproof composite material and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of science and technology, polymer composite materials have become increasingly prevalent in our daily lives. While these products have brought many conveniences to our lives, the potential dangers that come with them cannot be ignored. Most polymer materials are flammable, so we must attach great importance to the safe use of polymer products and take effective measures to prevent fire accidents. Epoxy resin (EP) has been widely used in adhesives, automotive machinery, material repair, aerospace, and other fields due to its excellent adhesion, heat and moisture resistance, corrosion resistance, and easy processing properties. However, the high crosslink density that can lead to brittle fracture of the resin and its inherent flammability have limited its further promotion in certain application areas. To overcome these shortcomings, researchers have been exploring modifications to the toughness and flame retardancy of epoxy resin.

[0003] Chinese invention patent publication number CN105694370A discloses a toughened and flame-retardant epoxy resin material and its preparation method. The toughened epoxy resin material comprises an epoxy resin monomer, a curing agent, expanded graphite, and flame-retardant microcapsules; wherein, by weight, the epoxy resin monomer comprises 70-95 parts by weight, the flame-retardant microcapsules comprise 5-25 parts by weight, the curing agent comprises 10-30 parts by weight, and the expanded graphite comprises 0.3-1 parts by weight, and the result is cured at 100-220°C. The flame-retardant microcapsules are prepared using ammonium polyphosphate with a molecular weight greater than 1500 as the core and a benzoxazine cross-linked network as the shell. The toughened and flame-retardant epoxy resin material disclosed in this invention achieves simultaneous improvement in both material toughness and flame retardancy, effectively overcoming the shortcomings of single-performance improvement methods for the material, but its mechanical properties need to be further improved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a fireproof composite material and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A fireproof composite material comprising the following raw materials in parts by weight: Epoxy resin: 60-80 parts, silicon dioxide: 20-30 parts, flame retardant: 10-18 parts, curing agent: 10-15 parts, toughening agent: 2-5 parts, accelerator: 1-2 parts, antioxidant: 1-3 parts; The toughening agent is prepared by the following method: S1: Trimesic acid reacts with oleyl alcohol to form a triester compound; the reaction equation is as follows: ; S2: 1,4-phenylenediboronic acid reacts with 3-mercapto-1,2-propanediol to form a dioxaborinyl heterocyclic compound; the reaction equation is as follows: ; S3: The triester compound reacts with the dioxaborin heterocyclic compound to form a toughening agent; in the reaction, the thiol in the dioxaborin heterocyclic compound and the carbon-carbon double bond in the triester compound undergo an addition reaction to form a hyperbranched polymer.

[0006] In step S1, the molar ratio of trimesic acid to oleyl alcohol is 1:(3-3.5).

[0007] In step S2, the molar ratio of 1,4-phenylenediboronic acid to 3-mercapto-1,2-propanediol is 1:(2-2.5).

[0008] In step S3, the molar ratio of the triester compound to the dioxaborin heterocyclic compound is (1.5-1.8):3.

[0009] The flame retardant is prepared by the following method: N1: 4,4'-diaminodiphenyl ether reacts with phenylphosphonic dichloride to form a linear polymer; the reaction equation is as follows: ; N2: Linear polymer reacts with γ-chloropropyltrimethoxysilane to form a flame retardant; the reaction equation is as follows: ; In step N1, the molar ratio of the 4,4'-diaminodiphenyl ether to phenylphosphonic dichloride is 1.2:1; in step N2, the mass ratio of the linear polymer to γ-chloropropyltrimethoxysilane is 20:1.

[0010] The curing agent is one of diethylenetriamine and aminoethylpiperazine.

[0011] The accelerator is one of 2-methylimidazole and 2-ethyl-4-methylimidazole.

[0012] The antioxidant is one of antioxidant 1010 and antioxidant 1076.

[0013] A method for preparing a fireproof composite material comprises the following steps: (1) Weigh by weight: epoxy resin: 60-80 parts, silicon dioxide: 20-30 parts, flame retardant: 10-18 parts, curing agent: 10-15 parts, toughening agent: 2-5 parts, accelerator: 1-2 parts, antioxidant: 1-3 parts; (2) The epoxy resin, silica, flame retardant, toughening agent and antioxidant are stirred and evenly mixed, and a curing agent and an accelerator are added and stirred. After heating and curing, a fireproof composite material is obtained.

[0014] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: (1) The toughening agent prepared in this application has a hyperbranched structure containing benzene rings, alkyl chains and dynamic borate bonds, which can significantly improve the impact resistance of fire-resistant composite materials.

[0015] (2) The flame retardant prepared in this application synergistically improves the flame retardant properties of the fireproof composite material by capturing active free radicals, dehydrating to form carbon, releasing non-combustible gas, and forming a surface heat-insulating carbon layer. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0017] Example 1 Preparation of toughening agent: S1: 500 ml of toluene, 0.1 mol of trimesic acid, 0.3 mol of oleyl alcohol, and 2 g of p-toluenesulfonic acid were added to a reaction flask in sequence, stirred and mixed, heated to 80°C, and reacted for 15 h (during which the generated water was separated by a water separator), cooled to room temperature, and the pH was adjusted to 7 with 1 M NaOH solution. The mixture was allowed to stand for stratification, washed three times with deionized water (300 ml each time), dried with 30 g of anhydrous magnesium sulfate, filtered, and distilled under reduced pressure at 80°C for 2 h to obtain a triester compound; its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d ) δ 8.66 (s, 3H), 5.45 (dddd, J = 5.5, 4.4, 2.1, 1.0Hz, 6H), 4.35 (t, J = 6.1 Hz, 6H), 2.10 - 1.96 (m, 12H), 1.86 - 1.71 (m, 6H),1.50 - 1.36 (m, 6H), 1.36 - 1.20 (m, 60H), 0.95 - 0.83 (m, 9H); S2: 400 ml of tetrahydrofuran, 0.6 g of deionized water, 0.2 mol of 3-mercapto-1,2-propanediol, and 0.1 mol of 1,4-phenylenediboronic acid were added to a reaction flask in sequence, stirred for 10 min, and 40 g of magnesium sulfate was added. The mixture was stirred at room temperature for 20 h, filtered, and distilled under reduced pressure at 40°C for 3 h to obtain a dioxaborin heterocyclic compound. Its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d) δ 7.70 (s, 4H), 4.61 (tt, J = 4.3, 3.4 Hz, 2H), 4.50 (dd, J = 10.4, 3.4Hz, 2H), 4.24 (dd, J = 10.4, 3.4 Hz, 2H), 2.77 (ddd, J = 12.1, 6.1, 4.3 Hz, 2H), 2.52 (ddd, J = 12.2, 6.2, 4.2 Hz, 2H), 1.73 (d, J = 12.4 Hz, 2H); S3: 1200 ml of anhydrous tetrahydrofuran, 0.15 mol of triester compound, 0.3 mol of dioxaborin heterocyclic compound, and 5 g of photoinitiator 184 were added to the reaction bottle in sequence, stirred and mixed, irradiated with 385 nm ultraviolet light for 4 min at room temperature, and distilled under reduced pressure at 40°C for 2 h to obtain the toughening agent.

[0018] Example 2 Preparation of toughening agent: S1: 500 ml of toluene, 0.1 mol of trimesic acid, 0.33 mol of oleyl alcohol, and 2 g of p-toluenesulfonic acid were added to a reaction flask in sequence, stirred and mixed, heated to 90°C, reacted for 12 h (during which the generated water was separated by a water separator), cooled to room temperature, adjusted the pH to 7 with 1 M NaOH solution, allowed to stand for stratification, washed three times with deionized water (300 ml each time), dried with 30 g of anhydrous magnesium sulfate, filtered, and distilled under reduced pressure at 80°C for 2 h to obtain a triester compound; S2: 400 ml of tetrahydrofuran, 0.6 g of deionized water, 0.23 mol of 3-mercapto-1,2-propanediol, and 0.1 mol of 1,4-phenylenediboronic acid were added to a reaction flask in sequence, stirred for 10 min, 40 g of magnesium sulfate was added, and the mixture was stirred at room temperature for 25 h. The mixture was filtered and distilled under reduced pressure at 40°C for 3 h to obtain a dioxaborin heterocyclic compound. S3: 1200 ml of anhydrous tetrahydrofuran, 0.16 mol of triester compound, 0.3 mol of dioxaborin heterocyclic compound, and 5 g of photoinitiator 184 were added to the reaction bottle in sequence, stirred and mixed, irradiated with 385 nm ultraviolet light for 8 min at room temperature, and distilled under reduced pressure at 40°C for 2 h to obtain the toughening agent.

[0019] Example 3 Preparation of toughening agent: S1: 500 ml of toluene, 0.1 mol of trimesic acid, 0.35 mol of oleyl alcohol, and 2 g of p-toluenesulfonic acid were added to a reaction flask in sequence, stirred and mixed, heated to 95°C, reacted for 10 h (during which the generated water was separated by a water separator), cooled to room temperature, adjusted the pH to 7 with 1 M NaOH solution, allowed to stand for stratification, washed three times with deionized water (300 ml each time), dried with 30 g of anhydrous magnesium sulfate, filtered, and distilled under reduced pressure at 80°C for 2 h to obtain a triester compound; S2: 400 ml of tetrahydrofuran, 0.6 g of deionized water, 0.25 mol of 3-mercapto-1,2-propanediol, and 0.1 mol of 1,4-phenylenediboronic acid were added to a reaction flask in sequence, stirred for 10 min, 40 g of magnesium sulfate was added, and the mixture was stirred at room temperature for 20 h. The mixture was filtered and distilled under reduced pressure at 40°C for 3 h to obtain a dioxaborin heterocyclic compound. S3: 1200 ml of anhydrous tetrahydrofuran, 0.18 mol of triester compound, 0.3 mol of dioxaborin heterocyclic compound, and 5 g of photoinitiator 184 were added to the reaction bottle in sequence, stirred and mixed, irradiated with 385 nm ultraviolet light for 8 min at room temperature, and distilled under reduced pressure at 40°C for 2 h to obtain the toughening agent.

[0020] Example 4 Preparation of flame retardant: N1: 400 ml of DMF and 0.12 mol of 4,4'-diaminodiphenyl ether were added to a reaction flask, stirred and mixed for 20 min, and 60 ml of a DMF solution containing 0.1 mol of phenylphosphonic dichloride was added dropwise over 1 h. The temperature was raised to 90°C and the reaction was continued for 6 h. The generated HCl was removed by nitrogen flow, and the reaction was cooled to room temperature. The reaction was then distilled under reduced pressure at 80°C for 3 h, and dried under vacuum at 80°C for 24 h to obtain a linear polymer. N2: Under ice bath, 1000 ml of anhydrous toluene, 10 g of γ-chloropropyltrimethoxysilane, 200 g of linear polymer, 0.15 mol of potassium carbonate and 1 g of potassium iodide were added to the reaction flask in sequence under nitrogen protection. The temperature was raised to 80 ° C for reaction for 24 h, cooled to room temperature, filtered, and distilled under reduced pressure at 70 ° C for 3 h. The flame retardant was obtained.

[0021] Example 5 Preparation of fireproof composite material: (1) Weigh: epoxy resin: 60g, silicon dioxide: 20g, flame retardant (prepared in Example 4): 10g, curing agent (diethylenetriamine): 10g, toughening agent (prepared in Example 1): 2g, accelerator (2-methylimidazole): 1g, antioxidant (antioxidant 1010): 1g; (2) Epoxy resin, silica, flame retardant, toughening agent and antioxidant were mixed, stirred at 90°C for 30 minutes, curing agent and accelerator were added and stirred for 20 minutes, cured at 100°C for 1 hour, cured at 120°C for 2 hours, and cured at 140°C for 3 hours, and cooled to room temperature to obtain a fire-resistant composite material.

[0022] Example 6 Preparation of fireproof composite material: (1) Weigh: epoxy resin: 70g, silicon dioxide: 25g, flame retardant (prepared in Example 4): 15g, curing agent (diethylenetriamine): 12g, toughening agent (prepared in Example 2): 4g, accelerator (2-methylimidazole): 1.5g, antioxidant (antioxidant 1076): 2g; (2) Epoxy resin, silica, flame retardant, toughening agent and antioxidant were mixed, stirred at 90°C for 30 minutes, curing agent and accelerator were added and stirred for 20 minutes, cured at 110°C for 1 hour, cured at 130°C for 2 hours, and cured at 150°C for 3 hours, and cooled to room temperature to obtain a fire-resistant composite material.

[0023] Example 7 Preparation of fireproof composite material: (1) Weigh: epoxy resin: 80 g, silicon dioxide: 30 g, flame retardant (prepared in Example 4): 18 g, curing agent (aminoethylpiperazine): 15 g, toughening agent (prepared in Example 3): 5 g, accelerator (2-ethyl-4-methylimidazole): 2 g, antioxidant (antioxidant 1076): 3 g; (2) Epoxy resin, silica, flame retardant, toughening agent and antioxidant were mixed, stirred at 90°C for 30 minutes, curing agent and accelerator were added and stirred for 20 minutes, cured at 120°C for 1 hour, cured at 140°C for 2 hours, and cured at 160°C for 3 hours, and cooled to room temperature to obtain a fire-resistant composite material.

[0024] Comparative Example 1 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the toughening agent added to the components (prepared in Example 2) is replaced by an equal weight of toughening agent prepared by the following method: The preparation method of the toughening agent is basically the same as that of Example 2, except that the trimesic acid in step S1 is replaced by an equimolar amount of tricarballylic acid.

[0025] Comparative Example 2 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the toughening agent added to the components (prepared in Example 2) is replaced by an equal weight of toughening agent prepared by the following method: The preparation method of the toughening agent is basically the same as that of Example 2, except that the oleyl alcohol in step S1 is replaced by an equimolar amount of crotyl alcohol.

[0026] Comparative Example 3 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the toughening agent added to the components (prepared in Example 2) is replaced by an equal weight of toughening agent prepared by the following method: S1: 500 ml of toluene, 0.1 mol of trimesic acid, 0.33 mol of oleyl alcohol, and 2 g of p-toluenesulfonic acid were added to a reaction flask in sequence, stirred and mixed, heated to 90°C, reacted for 12 h (during which the generated water was separated by a water separator), cooled to room temperature, adjusted the pH to 7 with 1 M NaOH solution, allowed to stand for stratification, washed three times with deionized water (300 ml each time), dried with 30 g of anhydrous magnesium sulfate, filtered, and distilled under reduced pressure at 80°C for 2 h to obtain a triester compound; S2: 1200 ml of anhydrous tetrahydrofuran, 0.16 mol of triester compound, 0.3 mol of 1,4-benzenedithiol, and 5 g of photoinitiator 184 were added to the reaction bottle in sequence, stirred and mixed, irradiated with 385 nm ultraviolet light for 8 min at room temperature, and distilled under reduced pressure at 40°C for 2 h to obtain the toughening agent.

[0027] Comparative Example 4 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the flame retardant added to the components (prepared in Example 4) is replaced by an equal weight linear polymer (prepared in step N1 of Example 4).

[0028] Comparative Example 5 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the flame retardant added to the components (prepared in Example 4) is replaced with a flame retardant of equal mass prepared by the following method: The preparation method of the flame retardant is substantially the same as that of Example 4, except that 4,4'-diaminodiphenyl ether in step N1 is replaced by an equal molar amount of 4,4'-diaminodiphenylmethane.

[0029] Comparative Example 6 The raw material composition and process of the fireproof composite material are basically the same as those of Example 6, except that the flame retardant added to the components (prepared in Example 4) is replaced with a flame retardant of equal mass prepared by the following method: The preparation method of the flame retardant is basically the same as that of Example 4, except that the amount of 4,4'-diaminodiphenyl ether added in step N1 is replaced with 0.24 mol.

[0030] The epoxy resin used in this application is bisphenol A epoxy resin, brand DER TM331, epoxy equivalent is 182g / eq; the model of silica is HL-200, produced by Hubei Huifu Nanomaterials Co., Ltd.

[0031] The fireproof composite materials prepared in Examples 5-7 and Comparative Examples 1-6 were tested for tensile strength, notched impact strength and flame retardancy.

[0032] The tensile strength test was conducted in accordance with GB / T 1040.2-2022 at a tensile speed of 50 mm / min using a 1A dumbbell specimen. The notched impact strength test was conducted in accordance with GB / T 1843-2008 using a V-notched specimen prepared by a notched prototyping machine. The flame retardancy test was conducted in accordance with GB / T 2406.2-2009. The test results are shown in Table 1.

[0033] Table 1 Performance test data table

[0034] It can be seen from Examples 5, 6 and 7 in Table 1 that the fireproof composite material prepared by the present invention has excellent mechanical strength and flame retardant properties.

[0035] The toughening agent prepared by the application has a hyperbranched structure, containing unreacted mercaptan, benzene ring, alkyl chain and dynamic borate bond. There are gaps in the three-dimensional network of the hyperbranched structure, which can absorb impact energy when the resin is impacted, thereby improving the toughness of the resin. Mercaptan can react with epoxy resin during the curing process to form a homogeneous toughening phenomenon. The benzene ring and the epoxy resin matrix can achieve efficient stress transmission through the π-π stacking effect, and the flexible alkyl chain can be deformed when subjected to external force, thereby absorbing and dissipating energy, which helps to improve the toughness and impact resistance of the material. The dynamic borate bond can dynamically rearrange the material when the material is subjected to external force, which can make the material better disperse stress, thereby improving the toughness of the material.

[0036] The flame retardant prepared in the present application contains elements such as P, N, and Si. Its linear polymer structure makes it easier to achieve uniform dispersion in the material, and it is not easy to migrate or precipitate when the material is used, maintaining a long-term and stable flame retardant effect. During combustion, the phosphorus element produces P-containing free radicals that inhibit combustion and promote the dehydration and carbonization of the material; the nitrogen element produces non-flammable gas and carbide; the silicon element promotes the formation of a dense, stable, and heat-insulating carbon layer; the rigid benzene ring structure can improve thermal stability and promote the formation of a graphitized carbon layer; multiple mechanisms work synergistically to achieve efficient flame retardancy of the material. The flexible ether bond in the flame retardant can absorb impact energy and improve the impact resistance of the material. The methylsiloxane in the flame retardant can condense with the hydroxyl groups on the surface of silica to improve the dispersibility of silica, thereby improving its mechanical properties.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by 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 are still within the scope of protection of the technical solution of the present invention.

Claims

1. A fireproof composite material, characterized in that: The composition comprises the following raw materials in parts by weight: Epoxy resin: 60-80 parts, silicon dioxide: 20-30 parts, flame retardant: 10-18 parts, curing agent: 10-15 parts, toughening agent: 2-5 parts, accelerator: 1-2 parts, antioxidant: 1-3 parts; The toughening agent is prepared by the following method: S1: Trimesic acid reacts with oleyl alcohol to form a triester compound; S2: 1,4-phenylenediboronic acid reacts with 3-mercapto-1,2-propanediol to form a dioxaborin heterocyclic compound; S3: The triester compound reacts with the dioxaborin heterocyclic compound to form a toughening agent.

2. The fireproof composite material according to claim 1, characterized in that: In step S1, the molar ratio of trimesic acid to oleyl alcohol is 1:(3-3.5).

3. The fireproof composite material according to claim 1, characterized in that: In step S2, the molar ratio of 1,4-phenylenediboronic acid to 3-mercapto-1,2-propanediol is 1:(2-2.5).

4. The fireproof composite material according to claim 1, characterized in that: In step S3, the molar ratio of the triester compound to the dioxaborin heterocyclic compound is (1.5-1.8):

3.

5. The fireproof composite material according to claim 1, characterized in that: The flame retardant is prepared by the following method: N1: 4,4'-diaminodiphenyl ether reacts with phenylphosphonic dichloride to form a linear polymer; N2: Linear polymer reacts with γ-chloropropyltrimethoxysilane to form a flame retardant.

6. The fireproof composite material according to claim 4, characterized in that: In step N1, the molar ratio of the 4,4'-diaminodiphenyl ether to phenylphosphonic dichloride is 1.2:1; in step N2, the mass ratio of the linear polymer to γ-chloropropyltrimethoxysilane is 20:

1.

7. The fireproof composite material according to claim 1, characterized in that: The curing agent is one of diethylenetriamine and aminoethylpiperazine.

8. The fireproof composite material according to claim 1, characterized in that: The accelerator is one of 2-methylimidazole and 2-ethyl-4-methylimidazole.

9. The fireproof composite material according to claim 1, characterized in that: The antioxidant is one of antioxidant 1010 and antioxidant 1076.

10. A method for preparing the fireproof composite material according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: epoxy resin: 60-80 parts, silicon dioxide: 20-30 parts, flame retardant: 10-18 parts, curing agent: 10-15 parts, toughening agent: 2-5 parts, accelerator: 1-2 parts, antioxidant: 1-3 parts; (2) The epoxy resin, silica, flame retardant, toughening agent and antioxidant are stirred and evenly mixed, and a curing agent and an accelerator are added and stirred. After heating and curing, a fireproof composite material is obtained.

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