Preparation and application of isopropanolamine modified ammonium polyphosphate flame-retardant epoxy resin

Abstract

This invention provides a method for preparing and applying isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin, relating to the field of flame-retardant modified polymer technology. The invention involves dissolving and mixing isopropanolamine and ammonium polyphosphate, heating them in a nitrogen atmosphere, and modifying the surface of the ammonium polyphosphate with isopropanolamine to obtain an isopropanolamine-modified ammonium polyphosphate flame retardant. This is then used as an organic filler in an epoxy resin, which is further cured to obtain the flame-retardant modified epoxy resin. The isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin prepared by this invention does not pollute the environment during thermal decomposition or combustion, and exhibits excellent flame-retardant properties, reducing the release of heat, smoke, and harmful gases during epoxy resin combustion, thereby reducing fire hazards.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant modified polymer materials technology, and in particular to the preparation and application of an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin. Background Technology

[0002] Epoxy resin is one of the most common thermosetting polymers, widely used in many engineering fields and daily life due to its excellent chemical resistance, mechanical properties, and adhesion. However, the inherent flammability of epoxy resin hinders its practical application in many areas. The large amount of heat and toxic fumes released during epoxy resin combustion are a major cause of death for humans and animals. Therefore, research on modified epoxy resin flame retardants with excellent flame retardancy, thermal stability, and smoke suppression properties is essential.

[0003] Flame retardants are widely used in everyday consumer goods. They are classified into halogenated and halogen-free flame retardants. Halogenated flame retardants produce large amounts of smoke and toxic, corrosive hydrogen halide gases during the flame retardation process, causing secondary hazards and are therefore gradually being banned. Halogen-free flame retardants, due to their low smoke and low toxicity, are widely used. Halogen-free flame retardants are mainly composed of phosphorus compounds and metal hydroxides. Among phosphorus-based flame retardants, intumescent flame retardants are highly valued in the halogen-free flame retardant field due to their high flame retardant efficiency. Intumescent flame retardants (IFR) are a composite, environmentally friendly, green flame retardant mainly composed of nitrogen and phosphorus, with a synergistic effect. IFRs generally include a carbon source (often a polyhydroxy compound, such as pentaerythritol), a phosphorus source (such as ammonium polyphosphate), and a foaming agent (such as melamine). Phosphorus-based flame retardants are rich in nitrogen and phosphorus elements. During combustion, ammonium polyphosphate not only exhibits solid-phase carbonization but also releases large amounts of non-flammable gases such as ammonia, achieving a gas-phase protection effect. And HPO present in the gas phase 2- , and PO - The free radical quenching effect further improves its flame retardant efficiency. However, the water sensitivity and high polarity of ammonium polyphosphate often lead to poor interfacial compatibility with the polymer matrix, which adversely affects various properties of the composite material. Therefore, to address the above-mentioned problems, we propose a method for preparing and applying isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin. Surface modification of ammonium polyphosphate can improve the flame retardant properties of the polymer, thereby enhancing both flame retardancy and economic efficiency. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing and applying an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin, which can improve the flame-retardant properties of the polymer and effectively solve the technical problems in the background art.

[0005] Technical Effects: This invention utilizes isopropanolamine to chemically modify the surface of ammonium polyphosphate, forming a POC structure, thereby effectively improving the quality of the carbon layer during combustion and further enhancing the flame retardant properties of the polymer. The isopropanolamine-modified ammonium polyphosphate flame retardant is then used as an organic filler in epoxy resin, and cured to obtain a green, halogen-free flame-retardant modified epoxy resin. The isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin prepared by this invention does not pollute the environment during pyrolysis or combustion, and possesses excellent flame-retardant properties, reducing the release of heat, smoke, and harmful gases during epoxy resin combustion, thus reducing fire hazards.

[0006] The further defined technical solution of this invention is: the preparation and application of an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin, comprising the following steps:

[0007] S1, Isopropanolamine and ammonium polyphosphate were added to a double-necked round-bottom flask, and then water was added to dissolve them. The mixture was stirred at high temperature under a nitrogen atmosphere, and then removed and cooled to room temperature. The mixture was filtered, separated, washed and dried to obtain isopropanolamine-modified ammonium polyphosphate flame retardant.

[0008] S2, add the isopropanolamine-modified ammonium polyphosphate obtained in step S1 to the epoxy resin and stir to obtain a mixture. Then heat the mixture, add an aromatic diamine curing agent and stir until uniform. Vacuum cure and cool to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0009] The beneficial effects of this invention are:

[0010] (1) The present invention provides a preparation and application of flame-retardant epoxy resin based on isopropanolamine-modified ammonium polyphosphate. The isopropanolamine and ammonium polyphosphate are dissolved in a double-necked round-bottom flask and subjected to high-temperature treatment in a nitrogen atmosphere to obtain an isopropanolamine-modified ammonium polyphosphate flame retardant. Then, epoxy resin and aromatic diamine curing agent are added to the isopropanolamine-modified ammonium polyphosphate flame retardant for treatment to obtain the isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin. The preparation process is simple, easy to control, and can improve the flame retardant performance.

[0011] (2) The preparation and application of the flame-retardant epoxy resin based on isopropanolamine-modified ammonium polyphosphate provided by the present invention is a phosphorus- and nitrogen-containing compound that has a certain hydrogen bond interaction with the polymer substrate and has good compatibility with environmental resins; and the isopropanolamine-modified ammonium polyphosphate flame retardant has abundant phosphorus and nitrogen flame-retardant elements, has obvious flame-retardant effect, and can act on both the gas phase and the solidified phase. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a diagram of the flame retardant product prepared in Example 1 of this invention;

[0014] Figure 2 This is a graph showing the heat release rate of Example 1 and Comparative Example 1 in this invention;

[0015] Figure 3 This is a graph showing the smoke release rate of Example 2 and Comparative Example 1 in this invention;

[0016] Figure 4 This is a graph showing the carbon monoxide formation rate of Example 3 and Comparative Example 1 in this invention;

[0017] Figure 5 This is a graph showing the carbon dioxide growth rate of Example 4 and Comparative Example 1 in this invention; Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention provides a method for preparing an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin, comprising the following steps:

[0020] S1, Isopropanolamine and ammonium polyphosphate were added to a double-necked round-bottom flask, and then water was added to dissolve them. The mixture was stirred at high temperature under a nitrogen atmosphere, and then removed and cooled to room temperature. The mixture was filtered, separated, washed and dried to obtain isopropanolamine-modified ammonium polyphosphate flame retardant.

[0021] Preferably, the mass ratio of isopropanolamine to ammonium polyphosphate is 0.5-1.5:1. Controlling this mass ratio is beneficial for the complete reaction and prevents other side reactions. More preferably, the mass ratio of isopropanolamine to ammonium polyphosphate is 0.8-1.2:1. If the mass ratio of isopropanolamine to ammonium polyphosphate is greater than 1.5:1, the excessive use of isopropanolamine will increase the preparation cost and will not promote further reaction. If the mass ratio of isopropanolamine to ammonium polyphosphate is less than 0.5:1, the amount of isopropanolamine used is too small, preventing the reaction from proceeding completely.

[0022] S2, the isopropanolamine-modified ammonium polyphosphate flame retardant obtained in step S1 is added to epoxy resin and stirred to obtain a mixture. Then the mixture is heated, and an aromatic diamine curing agent is added and stirred until uniform. Vacuum curing is performed and cooled to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame retardant epoxy resin.

[0023] Preferably, the epoxy resin is a bisphenol A type epoxy resin.

[0024] Preferably, the aromatic diamine curing agent is 4,4'-diaminodiphenylmethane, ethylenediamine, hexamethylenediamine, diaminodiphenylmethane, etc.; more preferably, the aromatic diamine curing agent is diaminodiphenylmethane.

[0025] Preferably, the mass ratio of isopropanolamine-modified ammonium polyphosphate flame retardant to epoxy resin is 5-35:100. If the mass ratio is less than 5:100, incomplete curing will occur; if the mass ratio is greater than 35:100, excessive curing agent will affect the performance of the composite material. In other embodiments, the mass ratio of isopropanolamine-modified ammonium polyphosphate flame retardant to epoxy resin is 1:15, 1:7, 3:13, or 1:3.

[0026] As a further preferred embodiment, the reaction temperature of the isopropanolamine-modified ammonium polyphosphate flame retardant and the epoxy resin is 85-120℃, and the reaction time is 40-60 min. Controlling the reaction temperature and reaction time is beneficial to the full progress of the reaction. Those skilled in the art can adjust the reaction temperature and time according to actual needs.

[0027] Preferably, the mass ratio of aromatic diamine curing agent to epoxy resin is 26-34:100. Controlling this mass ratio is beneficial for achieving better curing. If the mass ratio is greater than 34:100, the chemical reaction between the epoxy resin and the aromatic diamine curing agent will be incomplete, and too much aromatic diamine curing agent will affect the composite material. If the mass ratio is less than 26:100, the chemical reaction between the epoxy resin and the aromatic diamine curing agent will be incomplete, and too little aromatic diamine curing agent will result in an undry and rough cured surface, prone to honeycomb defects, and consequently, a decrease in cured hardness.

[0028] As a preferred method, the specific curing steps are as follows: curing at 70-90℃ for 0.5h, curing at 110-130℃ for 2h, and curing at 140-160℃ for 2h.

[0029] The present invention is an improvement based on an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0030] As a further improvement, this invention relates to the application of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin in flame retardants.

[0031] Example 1

[0032] A method for preparing an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin includes the following steps:

[0033] (1) Preparation of isopropanolamine-modified ammonium polyphosphate flame retardant: 25g isopropanolamine and 25g ammonium polyphosphate were added to a double-necked round-bottom flask, followed by 100mL deionized water and 200mL anhydrous ethanol for dissolution. The mixture was placed in a nitrogen atmosphere and stirred at 90℃ for 10h. After the reaction was completed, a mixture was obtained. The mixture was cooled to room temperature, filtered and separated, washed three times with anhydrous ethanol, and then dried under vacuum at 80℃ to obtain a white powder product.

[0034] (2) Preparation of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin: 5 parts of isopropanolamine-modified ammonium polyphosphate flame retardant were added to 75 parts of bisphenol A type epoxy resin and stirred to obtain a mixture. The mixture was then heated to 100℃ and reacted for 1 hour. 20 parts of diaminodiphenylmethane curing agent were added and stirred until homogeneous. The mixture was then vacuum-sealed to remove air bubbles and poured into a preheated mold. It was then cured sequentially at 80℃ for 0.5 hours, 120℃ for 2 hours, and 150℃ for 2 hours. After curing, it was naturally cooled to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0035] Example 2

[0036] A method for preparing isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin includes the following steps:

[0037] (1) Same as Example 1(1);

[0038] (2) Preparation of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin: 10 parts of isopropanolamine-modified ammonium polyphosphate flame retardant were added to 70 parts of bisphenol A type epoxy resin and stirred to obtain a mixture. The mixture was then heated to 100℃ and reacted for 1 hour. 20 parts of diaminodiphenylmethane curing agent were added and stirred until uniform. The mixture was then vacuum-sealed to remove air bubbles and poured into a preheated mold. It was then cured sequentially at 80℃ for 0.5 hours, 120℃ for 2 hours, and 150℃ for 2 hours. After curing, it was naturally cooled to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0039] Example 3

[0040] A method for preparing isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin includes the following steps:

[0041] (1) Same as Example 1(1);

[0042] (2) Preparation of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin: 15 parts of isopropanolamine-modified ammonium polyphosphate flame retardant were added to 65 parts of bisphenol A type epoxy resin and stirred to obtain a mixture. The mixture was then heated to 100℃ and reacted for 1 hour. 20 parts of diaminodiphenylmethane curing agent were added and stirred until uniform. The mixture was then vacuum-sealed to remove air bubbles and poured into a preheated mold. It was then cured sequentially at 80℃ for 0.5 hours, 120℃ for 2 hours, and 150℃ for 2 hours. After curing, it was naturally cooled to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0043] Example 4

[0044] A method for preparing isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin includes the following steps:

[0045] (1) Same as Example 1(1);

[0046] (2) Preparation of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin: 20 parts of isopropanolamine-modified ammonium polyphosphate flame retardant were added to 60 parts of bisphenol A type epoxy resin and stirred to obtain a mixture. The mixture was then heated to 100℃ and reacted for 1 hour. 20 parts of diaminodiphenylmethane curing agent were added and stirred until uniform. The mixture was then vacuum-sealed to remove air bubbles and poured into a preheated mold. It was then cured sequentially at 80℃ for 0.5 hours, at 120℃ for 2 hours, and at 150℃ for 2 hours. After curing, it was naturally cooled to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin.

[0047] Compare with Example 1

[0048] A method for preparing an epoxy resin flame retardant includes the following steps:

[0049] (1) Mix 80 parts of bisphenol A type epoxy resin and 20 parts of diaminodiphenylmethane curing agent evenly, then vacuum degas the mixture to remove air bubbles, and pour it into a preheated mold. Then cure it sequentially at 80℃ for 0.5h, 120℃ for 2h, and 150℃ for 2h. After curing, allow it to cool naturally to room temperature to obtain epoxy resin flame retardant.

[0050] Application Example 1

[0051] The flame retardants obtained in Examples 1-4 and Comparative Example 1 were placed in a cone calorimeter for cone calorimetry testing. The sample size of the flame retardant was 100mm × 100mm × 3mm. Figure 1 The graph shows the heat release rates of Example 1 and Control Example 1. Figure 2 The graph shows the smoke release rate of Example 2 and Control Example 1. Figure 3 The graph shows the carbon monoxide formation rates of Example 3 and Control Example 1. Figure 4 The graph shows the carbon dioxide generation rates of Example 4 and Control Example 1.

[0052] Depend on Figure 1 It can be seen that the heat release rate of Example 1 is 290 kW / m 2 Around 1080 kW / m², compared to the heat release rate of Example 1. 2 Example 1 has a lower heat release rate, and therefore has a higher flame retardant effect; Figure 2 It can be seen that the smoke release rate in Example 2 is 0.11m. 2 The smoke release rate is approximately 0.25 m / s, compared to 0.25 m / s for control example 1. 2 Example 2 has a lower smoke release rate of approximately / s, while Control Example 1 has a higher smoke release rate. Therefore, Example 2 produces less smoke during combustion, resulting in a lower fire hazard. Figure 3It can be seen that the carbon monoxide release rate of Example 3 is approximately 0.185 g / s, while that of Control Example 1 is approximately 0.38 g / s. Example 3 has a lower carbon monoxide release rate, while Control Example 1 has a higher carbon monoxide release rate. Therefore, Example 3 is more difficult to burn than Control Example 1 and has a better flame retardant effect. Figure 4 It can be seen that the carbon dioxide release rate of Example 4 is about 0.16 g / s, while the carbon dioxide release rate of Control Example 1 is about 0.73 g / s. Example 4 has a lower carbon dioxide release rate, while Control Example 1 has a higher carbon dioxide release rate. Therefore, Example 4 has a better flame retardant effect.

[0053] This invention relates to the preparation and application of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin. The invention modifies the surface of ammonium polyphosphate with isopropanolamine and uses it as an organic filler in the epoxy resin, curing the resulting isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin. This resin does not pollute the environment during thermal decomposition or combustion, reducing heat, smoke, and the release of harmful gases such as carbon monoxide and carbon dioxide during the combustion process, thereby reducing the risk of fire.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A process for the preparation of isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin, characterized in that, Includes the following steps: S1, Isopropanolamine and ammonium polyphosphate were added to a double-necked round-bottom flask, and then water was added to dissolve them. The mixture was stirred at high temperature under a nitrogen atmosphere, and then removed and cooled to room temperature. The mixture was filtered, separated, washed and dried to obtain isopropanolamine-modified ammonium polyphosphate flame retardant. S2, add the isopropanolamine-modified ammonium polyphosphate obtained in step S1 to the epoxy resin and stir to obtain a mixture. Then heat the mixture, add an aromatic diamine curing agent and stir until uniform. Vacuum cure and cool to room temperature to obtain isopropanolamine-modified ammonium polyphosphate flame retardant epoxy resin. The mass ratio of the isopropanolamine-modified ammonium polyphosphate flame retardant to the epoxy resin is 1:15; the mass ratio of the aromatic diamine curing agent to the epoxy resin is 26-34:100; the mass ratio of isopropanolamine to ammonium polyphosphate is 0.8-1.2:1; and the curing process is as follows: 70-90℃ for 0.5h, 110-130℃ for 2h, and 140-160℃ for 2h.

2. The method for preparing an isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin according to claim 1, characterized in that, The reaction temperature of the isopropanolamine-modified ammonium polyphosphate flame retardant and the epoxy resin is 85-120℃, and the reaction time is 40-60 min.

3. An isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin prepared by the method according to any one of claims 1-2.

4. The application of the isopropanolamine-modified ammonium polyphosphate flame-retardant epoxy resin according to claim 3 in flame retardants.

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