Hydrazinotriazine macromolecular charring agent as well as preparation method and application thereof

Abstract

The invention discloses a hydrazinotriazine macromolecular charring agent as well as a preparation method and application thereof, relates to the field of intumescent flame retardance, and aims to solve the problems of high organic solvent consumption and poor ageing resistance in the synthesis and application processes of the existing charring agent. The preparation method of the hydrazinotriazine macromolecular charring agent comprises the following steps: 1, dissolving monoamine in a NaOH aqueous solution to obtain a mixed solution A; 2, dispersing cyanuric chloride in a reaction container; 3, firstly dropwise adding triethylamine, and then dropwise adding the mixed solution A to obtain a hydrophobic white intermediate; 4, dissolving hydrazine in a NaOH aqueous solution to obtain a mixed solution B; diamine is dissolved in a NaOH aqueous solution, and a mixed solution C is obtained; dropwise adding the mixed solution B into the white intermediate, then dropwise adding the mixed solution C, heating, and carrying out reflux reaction; and 5, washing and drying the product. The method does not involve dangerous raw materials and reagents, the reaction conditions are milder and safer, and the anti-aging performance is higher. The method is used for improving the flame retardance and aging resistance of the high polymer material.

Description

Technical Field

[0001] This invention relates to the field of intumescent flame retardants, specifically to a hydrazine-based triazine macromolecular char-forming agent, its preparation method, and its application. Background Technology

[0002] Polyolefins and other polymeric materials possess advantages such as low density, high mechanical strength, corrosion resistance, and ease of processing and molding, leading to their wide application in industrial engineering, production, and daily life sectors, including automotive, transportation, and building materials. For example, PP (polypropylene) is widely used. However, with the increasing multifunctionality of PP products, its flammability, excessive dripping, and difficulty in extinguishing have become serious problems. Furthermore, during actual use, PP materials are exposed to heat, oxygen, and light, generating active free radicals and causing polymer chain breakage, resulting in aging and degradation, thus limiting the service life of PP materials. Therefore, during the processing of PP materials, flame retardants need to be added to impart excellent flame-retardant properties, while anti-aging agents are needed to slow down material aging and extend the material's service life.

[0003] Currently, there are many commercially available flame retardants, playing important roles in various materials. Halogen-free flame retardancy is commonly used in PP materials, with intumescent flame retardants (IFRs) being the most common additive. IFRs are characterized by low smoke, low toxicity, and environmental friendliness, exhibiting both gas-phase and condensed-phase flame retardant mechanisms. In multi-component intumescent flame retardant systems, polyphosphates are often used as acid sources, while triazine derivatives are used as gas and carbon sources. Widely used triazine substances are mainly designed and synthesized from cyanuric chloride. The three chlorine atoms in their structure can undergo nucleophilic substitution reactions, and the reactivity of these three chlorine atoms differs, allowing for the synthesis of various charring agents. However, the synthesis of triazine charring foaming agents requires the use of large amounts of low-boiling-point organic solvents such as acetone and tetrahydrofuran, leading to serious environmental and potential safety issues in actual production. Furthermore, achieving aging resistance mainly relies on adding hindered amines or hindered phenolic anti-aging agents to the material. By capturing free radicals generated during the aging process of PP, the aging resistance effect is achieved. However, hindered amine or hindered phenolic anti-aging agents have poor migration and extraction resistance in PP materials. In particular, these anti-aging agents interact with APP and other intumescent flame retardants, causing a decrease or failure in anti-aging efficiency, thereby affecting the anti-aging performance of intumescent flame retardant polypropylene materials and limiting their application scale to some extent. Summary of the Invention

[0004] The present invention aims to solve the problems of large amounts of organic solvents and poor anti-aging properties in the synthesis and application of existing charring agents, and to provide a hydrazine triazine macromolecular charring agent, its preparation method and application.

[0005] The structure of the hydrazine macromolecular char-forming agent of the present invention is as follows:

[0006]

[0007] Where R1 is an organic amino group, R2 is an organic diamino group, n ranges from 1 to n to 20, and m ranges from 5 to m to 50.

[0008] The organic amino group is one or more of methylamino, ethylamino, propylamino, dimethylamino, and diethylamino.

[0009] The organic diamino group is , NH2(CH2) x One or more of NH2, where x is an integer between 2 and 6.

[0010] This invention provides a method for preparing a hydrazine-based triazine macromolecular char-forming agent, comprising the following steps:

[0011] Step 1: Dissolve the monoamine in NaOH aqueous solution to obtain mixed solution A, and cool it to 0-10℃. Separately, take a certain amount of triethylamine and cool it to 0-10℃ for later use.

[0012] Step 2: Place the ice-salt water in the reaction vessel, which is equipped with a mechanical stirrer and an external ice-salt bath cooling device, and disperse the cyanuric chloride in the reaction vessel.

[0013] Step 3: First, add triethylamine to the reaction vessel, then add mixed solution A, keeping the temperature below 0℃ and the pH value between 6 and 7. After the addition is complete, a hydrophobic white intermediate is obtained.

[0014] Step 4: Dissolve hydrazine in NaOH aqueous solution to obtain mixed solution B; dissolve diamine in NaOH aqueous solution to obtain mixed solution C; first add mixed solution B dropwise to the white intermediate, and then add mixed solution C dropwise after completion. During the dropwise addition, keep the pH neutral and continuously raise the temperature to 100℃. Reflux the reaction for 4-10 hours and recover the catalyst triethylamine.

[0015] Step 5: After the reaction is complete, filter while hot to obtain the product. Wash the product with water and dry it to obtain the hydrazine macromolecular char-forming agent.

[0016] Furthermore, the monoamine mentioned in step one is one or a mixture of several of methylamine, ethylamine, propylamine, dimethylamine, and diethylamine.

[0017] Furthermore, the mass concentration of the NaOH aqueous solution in step one is 5% to 30%.

[0018] Furthermore, the molar ratio of the monoamine to NaOH in step one is 1:1.

[0019] Furthermore, the molar ratio of triethylamine to cyanuric chloride is (0.01~1):1.

[0020] Furthermore, in step four, the mass concentration of the NaOH aqueous solution is 5% to 30%.

[0021] Furthermore, the molar ratio of hydrazine to NaOH in mixed solution B is 1:2.

[0022] Furthermore, the molar ratio of diamine to NaOH in mixed solution C is 1:2.

[0023] Furthermore, in step four, the molar ratio of hydrazine to diamine is (0.05~1):1.

[0024] Furthermore, the total molar amount of hydrazine and diamine is the same as the molar amount of cyanuric chloride.

[0025] Furthermore, in step four, when adding mixed solution B, the reaction temperature of the system is controlled below 50°C.

[0026] Furthermore, stirring is required during steps two through five at a rate of 300-500 r / min to ensure that the reactants are evenly dispersed in the system and to prevent side reactions caused by excessively high local alkalinity concentrations.

[0027] The hydrazine macromolecular char-forming agent of the present invention is used to improve the flame retardancy and aging resistance of polymer materials.

[0028] Preferably, the polymer material is a polyolefin, an elastomer, or a coating.

[0029] Specific methods to improve the flame retardancy and aging resistance of polymer materials are as follows:

[0030] Hydrazine macromolecular charring agent, ammonium polyphosphate (APP) and nano-silica (Nano-SiO2) are mixed evenly in a high-speed pulverizer to prepare an intumescent flame retardant. The intumescent flame retardant is then mixed with polymer materials, extruded and pelletized in a twin-screw extruder, and then injection molded through an injection molding machine.

[0031] The mass ratio of hydrazine macromolecular char-forming agent, ammonium polyphosphate, and nano silica is 19:76:5.

[0032] The beneficial effects of this invention are:

[0033] This invention provides a hydrazine-based triazine macromolecular charring agent that combines charring, flame retardant, and anti-aging functions. In the preparation process, triethylamine is used as a reaction catalyst. By controlling the appropriate amount of triethylamine, the nucleophilic substitution reaction of cyanuric chloride is achieved under aqueous conditions. Pure water is used as the solvent, avoiding the use of flammable and explosive hazardous raw materials such as acetone and tetrahydrofuran, resulting in milder reaction conditions, safer operation, and higher yield.

[0034] Hydrazine macromolecular charring agents can generate non-combustible gases such as N2, NH3, and H2O during combustion, providing a sufficient gas source for the intumescent flame retardant system. By adjusting the appropriate ratio of hydrazine to diamine, the gas production of IFR during combustion is moderate, and the expansion and density of the char layer reach the optimal values, giving the polymer material the best flame retardant properties. Hydrazine can capture free radicals generated during the aging process of polymer materials, thereby delaying the aging process of polymer materials.

[0035] The IFR prepared by mixing hydrazine macromolecular charring agent with APP and Nano-SiO2 can impart excellent flame retardant properties to polymer materials such as PP at a low addition amount, providing a new solution to the problems of flammability and poor aging resistance of polymer materials, and has good application prospects and practical value. Attached Figure Description

[0036] Figure 1 The methylamine-triazine-piperazine-hydrazine macromolecular charring agent prepared in Example 1 13 C NMR spectrum;

[0037] Figure 2 The methylamine-triazine-piperazine-hydrazine macromolecular charring agent prepared in Example 2 13 C NMR spectrum;

[0038] Figure 3 The methylamine-triazine-piperazine macromolecule prepared for Comparative Example 1 13 C NMR spectrum;

[0039] Figure 4 Infrared spectra of the products from Examples 1, 2 and 1. Detailed Implementation

[0040] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0041] Specific Implementation Method 1: The structure of the hydrazine-triazine macromolecular charring agent in this implementation method is as follows:

[0042]

[0043] Where R1 is an organic amino group, R2 is an organic diamino group, n ranges from 1 to n to 20, and m ranges from 5 to m to 50.

[0044] The organic amino group is one or more of methylamino, ethylamino, propylamino, dimethylamino, and diethylamino.

[0045] The organic diamino group is , NH2(CH2) x One or more of NH2, where x is an integer between 2 and 6.

[0046] This invention addresses the need for a highly efficient, safe, inexpensive, and high-performance integrated flame retardant and aging-resistant agent. Through nucleophilic reactions, using cyanuric chloride, monoamines, hydrazine, and diamines as raw materials and triethylamine as a catalyst, a series of hydrazine-based triazine macromolecules were prepared under pure water conditions. These hydrazine-based triazine macromolecules, acting as char-forming agents, are then combined with APP and Nano-SiO2 to prepare IFR (Integrated Flame Retardant). This effectively solves the problems of low flame retardant efficiency, insufficient gas production, high costs, environmental pollution, and safety concerns associated with traditional char-forming foaming agents. It also addresses the migration issues of small-molecule antioxidants. Without adding other components, it imparts excellent aging resistance to polymer materials such as PP, aligning with the era of multi-functional products and the development concept of energy conservation.

[0047] Specific Implementation Method Two: The preparation method of the hydrazine-based triazine macromolecular char-forming agent in this implementation method includes the following steps:

[0048] Step 1: Dissolve the monoamine in NaOH aqueous solution to obtain mixed solution A, and cool it to 0-10℃. Separately, take a certain amount of triethylamine and cool it to 0-10℃ for later use.

[0049] Step 2: Place the ice-salt water in the reaction vessel, which is equipped with a mechanical stirrer and an external ice-salt bath cooling device, and disperse the cyanuric chloride in the reaction vessel.

[0050] Step 3: First, add triethylamine to the reaction vessel, then add mixed solution A, keeping the temperature below 0℃ and the pH value between 6 and 7. After the addition is complete, a hydrophobic white intermediate is obtained.

[0051] Step 4: Dissolve hydrazine in NaOH aqueous solution to obtain mixed solution B; dissolve diamine in NaOH aqueous solution to obtain mixed solution C; first add mixed solution B dropwise to the white intermediate, and then add mixed solution C dropwise after completion. During the dropwise addition, keep the pH neutral and continuously raise the temperature to 100℃. Reflux the reaction for 4-10 hours and recover the catalyst triethylamine.

[0052] Step 5: After the reaction is complete, filter while hot to obtain the product. Wash the product with water and dry it to obtain the hydrazine macromolecular char-forming agent.

[0053] Specific Implementation Method 3: In step one of this implementation method, the monoamine is one or a mixture of several of the following: methylamine, ethylamine, propylamine, dimethylamine, and diethylamine. Other steps and parameters are the same as in Specific Implementation Method 2.

[0054] Specific Implementation Method Four: In step one of this implementation method, the mass concentration of the NaOH aqueous solution is 5%~30%. Other steps and parameters are the same as in Specific Implementation Method Two or Three.

[0055] Specific Implementation Method 5: In this implementation method, the molar ratio of the monoamine to NaOH in step one is 1:1. Other steps and parameters are the same as in Specific Implementation Method 4.

[0056] Specific Implementation Method Six: In this implementation method, the molar ratio of triethylamine to cyanuric chloride is (0.01~1):1. Other steps and parameters are the same as in Specific Implementation Methods Two to Five.

[0057] Specific Implementation Method Seven: In step four of this implementation method, the mass concentration of the NaOH aqueous solution is 5%~30%. Other steps and parameters are the same as in Specific Implementation Method Two.

[0058] Specific Implementation Method Eight: In this implementation method, the molar ratio of hydrazine to NaOH in mixed solution B is 1:2. Other steps and parameters are the same as in Specific Implementation Method Seven.

[0059] Specific Implementation Method Nine: In this implementation method, the molar ratio of diamine to NaOH in mixed solution C is 1:2. Other steps and parameters are the same as in Specific Implementation Method Seven or Eight.

[0060] Specific Implementation Method Ten: In step four of this implementation method, the molar ratio of hydrazine to diamine is (0.05~1):1. Other steps and parameters are the same as in any one of Specific Implementation Methods Two to Nine.

[0061] Specific Implementation Method Eleven: In this implementation method, the total molar amounts of hydrazine and diamine are the same as the molar amounts of cyanuric chloride. Other steps and parameters are the same as in Specific Implementation Methods Two through Ten.

[0062] Specific Implementation Method Twelve: In step four of this implementation method, when adding mixed solution B, the reaction temperature of the system is controlled below 50°C. Other steps and parameters are the same as in Specific Implementation Methods Two through Eleven.

[0063] Specific Implementation Method Thirteen: In this implementation method, stirring is required during steps two to five of the reaction process. The stirring rate is 300-500 r / min to ensure that the reactants are uniformly dispersed in the system and to avoid excessively high local alkalinity concentrations that could lead to side reactions. Other steps and parameters are the same as in Specific Implementation Methods Two to Twelve.

[0064] Specific Implementation Method Fourteen: In this implementation method, hydrazine-based triazine macromolecular charring agent is used to improve the flame retardant and aging resistance properties of polymer materials.

[0065] Specific Implementation Method Fifteen: The polymer materials described in this implementation method are polyolefins, elastomers, and coatings. Other steps and parameters are the same as in Specific Implementation Method Fourteen.

[0066] Specific Implementation Method Sixteen: The specific method for improving the flame retardant and aging resistance properties of polymer materials in this implementation method is as follows:

[0067] Hydrazine macromolecular charring agent, ammonium polyphosphate (APP), and nano-silica (Nano-SiO2) are mixed evenly in a high-speed pulverizer to prepare an intumescent flame retardant. The intumescent flame retardant is then mixed with polymer materials, extruded and pelletized in a twin-screw extruder, and injection molded. Other steps and parameters are the same as in specific embodiment fourteen.

[0068] Specific Implementation Method Seventeen: In this implementation method, the mass ratio of hydrazine macromolecular char-forming agent, ammonium polyphosphate, and nano-silica is 19:76:5. Other steps and parameters are the same as in Specific Implementation Method Sixteen.

[0069] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0070] Example 1:

[0071] The preparation method of the hydrazine macromolecular char-forming agent in this embodiment includes the following steps:

[0072] Step 1: Dissolve 62g of 30% methylamine aqueous solution (0.6mol) in NaOH aqueous solution to obtain mixed solution A, and cool it to 0℃. Separately, take 6.06g of triethylamine and cool it to 0℃ for later use. The NaOH aqueous solution is prepared by dissolving 24g of NaOH in 100g of water.

[0073] Step 2: Place 600g of -5℃ ice-salt water into a four-necked round-bottom flask, and equip it with a mechanical stirrer and an external ice-salt bath cooling device to disperse 110.64g of cyanuric chloride in the four-necked round-bottom flask;

[0074] Step 3: First add triethylamine to the flask, then add mixed solution A, keeping the temperature below 0℃ and the pH value between 6 and 7. After the addition is complete, a hydrophobic white intermediate is obtained.

[0075] Step 4: Dissolve 30g of 50% hydrazine hydrate in NaOH aqueous solution to obtain mixed solution B; dissolve 25.84g of piperazine in NaOH aqueous solution to obtain mixed solution C; first add mixed solution B dropwise to the white intermediate, keeping the reaction temperature below 50℃, then add mixed solution C dropwise, maintaining the pH at neutral during the addition process, continuously raising the reaction temperature to 100℃, refluxing for 8 hours, and recovering the catalyst triethylamine (where the molar ratio of hydrazine to piperazine is 1:1); the NaOH aqueous solution is prepared by dissolving 24g of NaOH in 100g of water.

[0076] Step 5: After the reaction is complete, filter while hot to obtain the product. Wash the product three times with water and dry it in a vacuum drying oven at 90°C for 12 hours to obtain methylamine-triazine-piperazine-hydrazine macromolecular oligomer (CFA1).

[0077] The structural formula of the product CFA1 obtained in this embodiment is:

[0078] , where 40≤m≤50.

[0079] The product CFA1 obtained in this embodiment 13 C NMR characterization as follows Figure 1 As shown in the CFA1 test results, peak a at 167.04 ppm is generated by the C on the triazine ring, peak b at 43.06 ppm is formed by the C on the piperazine, and peak c at 27.73 ppm is formed by the C on the methyl group.

[0080] Example 2:

[0081] The preparation method of the hydrazine macromolecular char-forming agent in this embodiment includes the following steps:

[0082] Step 1: Dissolve 62g of 30% methylamine aqueous solution (0.6mol) in NaOH aqueous solution to obtain mixed solution A, and cool it to 0℃. Separately, take 6.06g of triethylamine and cool it to 0℃ for later use. The NaOH aqueous solution is prepared by dissolving 24g of NaOH in 100g of water.

[0083] Step 2: Place 600g of -5℃ ice-salt water into a four-necked round-bottom flask, and equip it with a mechanical stirrer and an external ice-salt bath cooling device to disperse 110.64g of cyanuric chloride in the four-necked round-bottom flask;

[0084] Step 3: First add triethylamine to the flask, then add mixed solution A, keeping the temperature below 0℃ and the pH value between 6 and 7. After the addition is complete, a hydrophobic white intermediate is obtained.

[0085] Step 4: Dissolve 10g of 50% hydrazine hydrate in an aqueous NaOH solution (the NaOH solution is prepared by dissolving 8g of NaOH in 33g of water) to obtain mixed solution B; dissolve 43.07g of piperazine in an aqueous NaOH solution (the NaOH solution is prepared by dissolving 40g of NaOH in 165g of water) to obtain mixed solution C; first add mixed solution B dropwise to the white intermediate, keeping the reaction temperature below 50℃, and then add mixed solution C dropwise after the reaction is complete, keeping the pH neutral during the addition process. Continuously raise the reaction temperature to 100℃, reflux for 12 hours, and recover the catalyst triethylamine (where the molar ratio of hydrazine to piperazine is 1:5).

[0086] Step 5: After the reaction is complete, filter while hot to obtain the product. Wash the product three times with water and dry it in a vacuum drying oven at 90°C for 12 hours to obtain methylamine-triazine-piperazine-hydrazine macromolecular oligomer (CFA2).

[0087] The structural formula of the product CFA2 obtained in this embodiment is:

[0088] , where 15≤m≤20.

[0089] The product CFA2 obtained in this embodiment 13 C NMR characterization as follows Figure 2 As shown in the CFA2 test results, peak a at 166.80 ppm is generated by the C on the triazine ring, peak b at 42.65 ppm is formed by the C on the piperazine, and peak c at 27.46 ppm is formed by the C on the methyl group.

[0090] Comparative Example 1:

[0091] This comparative example provides a method for preparing methylamine-triazine-piperazine macromolecular oligomers, in which hydrazine is not added:

[0092] Step 1: Dissolve 62g of 30% methylamine aqueous solution (0.6mol) in NaOH aqueous solution to obtain mixed solution A, and cool it to 0℃. Separately, take 6.06g of triethylamine and cool it to 0℃ for later use. The NaOH aqueous solution is prepared by dissolving 24g of NaOH in 100g of water.

[0093] Step 2: Place 600g of -5℃ ice-salt water into a four-necked round-bottom flask, and equip it with a mechanical stirrer and an external ice-salt bath cooling device to disperse 110.64g of cyanuric chloride in the four-necked round-bottom flask;

[0094] Step 3: First add triethylamine to the flask, then add mixed solution A, keeping the temperature below 0℃ and the pH value between 6 and 7. After the addition is complete, a hydrophobic white intermediate is obtained.

[0095] Step 4: Dissolve 51.68g of piperazine in an aqueous NaOH solution (the NaOH solution is prepared by dissolving 48g of NaOH in 200g of water) to obtain mixed solution C; add mixed solution C dropwise to the white intermediate, keeping the pH neutral during the dropwise addition, and controlling the reaction temperature below 50℃. When half of the dropwise addition is completed, continuously raise the reaction temperature to 100℃, reflux for 12 hours, and recover the catalyst triethylamine (where the molar ratio of hydrazine to piperazine is 0).

[0096] Step 5: After the reaction is complete, filter while hot to obtain the product. Wash the product three times with water and dry it in a vacuum drying oven at 90°C for 12 hours to obtain methylamine-triazine-piperazine macromolecule (CFA3).

[0097] The structural formula of the product CFA3 obtained in this comparative example is:

[0098] , where 80≤m≤100.

[0099] The resulting product CFA3 13 C NMR characterization as follows Figure 3 As shown. From Figure 3 As can be seen from the results, peak a at 165.82 ppm in the CFA3 test results is generated by the C on the triazine ring, peak b at 42.31 ppm is formed by the C on the piperazine, and peak c at 27.64 ppm is formed by the C on the methyl group.

[0100] Infrared characterization of products CFA1, CFA2, and CFA3 in Examples 1, 2, and Comparative Example 1 is as follows: Figure 4 As shown. From Figure 4 As can be seen from this, 3274cm -1 and -3441cm -1 The NH absorption peak at 2867 cm⁻¹ exhibits a wider absorption range and enhanced absorption with increasing hydrazine content. -1 and 2941 cm -1 The two infrared absorption peaks at 1550 cm⁻¹ correspond to the stretching vibration absorption peaks of the CH bonds on the methyl and piperazine rings, respectively. -1 1430 cm -1 and 800 cm -1 The infrared absorption peak at 848 cm⁻¹ is the vibrational absorption peak of the triazine ring skeleton. -1The absence of an absorption peak at the C-Cl bond (attached to the triazine ring) indicates that all three chlorine atoms on the cyanuric chloride have been substituted. Preliminary infrared spectroscopy analysis confirms the successful synthesis of the product.

[0101] Application effect verification:

[0102] (I) Preparation of PP and aging-resistant PP / CFA composite materials

[0103] The products synthesized in Examples 1, 2 and Comparative Example 1 (CFA1, CFA2 and CFA3) were added to PP / CFA1, PP / CFA2 and PP / CFA3 composite materials with 95.2 wt.% PP at an addition amount of 4.8 wt.%.

[0104] First, CFA1, CFA2, and CFA3 are uniformly mixed with PP powder in a high-speed pulverizer. Then, the mixed material is extruded in a twin-screw extruder at a screw speed of 15 Hz. After extrusion, the material is granulated in a granulator and then vacuum dried at 85°C for 4 hours. The heating zones of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 180°C, 175°C, and 180°C, respectively. The dried granules are then injection molded in an injection molding machine to produce a series of standard test specimens for performance testing.

[0105] The PP and composite materials were subjected to aging treatment at 120℃ for 144 hours. Their aging performance was tested by the changes in mechanical properties before and after the treatment. The results are shown in Table 1 below.

[0106] Table 1 Mechanical properties of PP composite materials before and after aging

[0107]

[0108] As can be clearly seen from Table 1, the hydrazine macromolecular oligomers containing hydrazine groups (CFA1 and CFA2) showed significantly improved tensile strength, flexural strength, and impact strength of the PP composite material after heat aging compared with the hydrazine macromolecular oligomer without hydrazine groups synthesized in Comparative Example 1 (CFA3) and pure PP. This indicates that the hydrazine macromolecular oligomers containing hydrazine groups have significant heat aging resistance, and the higher the hydrazine content, the better the heat aging resistance.

[0109] (II) Preparation of PP and flame-retardant and aging-resistant PP / IFR composite materials

[0110] The products synthesized in Examples 1, 2, and Comparative Example 1 (CFA1, CFA2, and CFA3), APP, and Nano-SiO2 were mixed uniformly in a high-speed pulverizer at a ratio of 19:76:5 to prepare intumescent flame retardants (IFR1, IFR2, and IFR3). These were then uniformly mixed with polypropylene (PP) at an addition amount of 24 wt.% in a high-speed pulverizer. The mixed material was then extruded in a twin-screw extruder at a screw speed of 15 Hz. After extrusion, the material was pelletized on a pelletizer and then vacuum dried at 85°C for 4 h. The heating zones of the twin-screw extruder were 170°C, 175°C, 180°C, 180°C, 180°C, 175°C, and 180°C, respectively. The dried pellets were then injection molded on an injection molding machine to produce a series of standard test specimens for performance testing.

[0111] The flame retardant properties of the flame-retardant and aging-resistant PP / IFR composite material were characterized by vertical burning (UL-94) and limiting oxygen index (LOI) tests, and the results are shown in Table 2 below.

[0112] Table 2. LOI and UL-94 data for flame-retardant and aging-resistant PP composite materials.

[0113]

[0114] As can be seen from Table 2, the intumescent flame retardants (IFR1 and IFR2) containing hydrazine macromolecular oligomers (CFA1 and CFA2) have a higher hydrazine content than the comparative intumescent flame retardant (IFR3) containing hydrazine macromolecular oligomers (CFA3) and pure PP. The higher hydrazine content is detrimental to flame retardancy (e.g., the 1.6 mm thick PP / IFR sample cannot pass the UL-94 V-0 rating). However, by appropriately adjusting the hydrazine content, excellent flame retardant performance can be exhibited, and the UL-94 V-0 rating can be passed.

[0115] The above-mentioned PP and flame-retardant and aging-resistant PP / IFR composite materials were subjected to aging treatment at 120℃ for 144h. Their aging performance was tested by the changes in mechanical properties before and after the treatment. The results are shown in Table 3 below.

[0116] Table 3 Mechanical properties of flame-retardant and aging-resistant PP / IFR composite materials before and after aging.

[0117]

[0118] As shown in Table 3, the intumescent flame retardants (IFR1 and IFR2) containing hydrazine macromolecular oligomers (CFA1 and CFA2) exhibit significantly improved tensile strength, flexural strength, and impact strength after heat aging compared to the comparative intumescent flame retardant (IFR3) containing hydrazine macromolecular oligomers (CFA3) and pure PP. This indicates that the hydrazine macromolecular oligomers containing hydrazine have significant heat aging resistance, and the higher the hydrazine content, the better the heat aging resistance.

[0119] In summary, the above experiments demonstrate that: 1) Under aqueous conditions, using triethylamine as a catalyst, the preparation of hydrazine macromolecules was achieved, and infrared analysis and... 13 Solid-state NMR spectroscopy results confirmed the successful synthesis of the product structure of this invention. This invention solves the problems of organic solvent waste and production safety in the preparation of triazine macromolecules. 2) The hydrazine group in the hydrazine macromolecule has a free radical scavenging function, which can capture free radicals generated during the aging process of polymer materials such as PP, inhibit the aging process of materials, and maintain the mechanical properties of materials well, thus endowing the composite material with excellent aging resistance. 3) The diamine structure in the hydrazine macromolecule has a char-promoting function, making it easier to form a dense char layer during polymer combustion. 4) The IFR obtained by mixing hydrazine macromolecules with APP and Nano-SiO2 in a ratio of 19:76:15 can exhibit excellent flame retardant properties in polymer materials such as PP, with a high LOI value, and can pass the Ul-94 V-0 level. Moreover, there is an optimal ratio of hydrazine to diamine in the hydrazine macromolecule, which makes the constructed IFR endow PP and other polymer materials with better flame retardant properties. 5) The flame retardant properties of IFR-enriched polymer materials constructed by hydrazine macromolecular charring agents come from the heat insulation and oxygen barrier effect of the char layer generated during combustion, the dilution effect of non-combustible gases on small molecule combustibles and oxygen, and the free radical capture function of OH· and H·.

Claims

1. A hydrazine-based triazine macromolecular char former, characterized in that, The structure of the macromolecular charring agent is as follows: wherein R1 is an organic amino group, R2 is an organic diamino group, n is in the range of 1≤n≤20, and m is in the range of 5≤m≤50.

2. The hydrazine-based triazine macromolecular char former according to claim 1, characterized in that, The organic amino group is one or more of methylamino, ethylamino, propylamino, dimethylamino, and diethylamino.

3. The hydrazine-based triazine macromolecular char former according to claim 1 or 2, characterized in that, The organic diamino is 、 , NH2(CH2) x one or several of NH2, wherein x is an integer between 2 and 6.

4. The process for preparing hydrazine-based triazine macrochar according to claim 1, characterized in that, The method comprises the following steps: Step one: dissolve a monoamine in a NaOH aqueous solution to obtain a mixed solution A, and cool to 0-10℃, and take another amount of triethylamine and cool to 0-10℃ for standby; Step two: place ice-salt water in a reaction container, which is equipped with a mechanical stirring device and an external ice-salt bath cooling device, and disperse cyanuric chloride in the reaction container; Step three: add triethylamine to the reaction container first, and then add the mixed solution A, keeping the temperature below 0℃ and the pH value at 6-7, to obtain a hydrophobic white intermediate after the addition is completed; Step four: dissolve hydrazine in a NaOH aqueous solution to obtain a mixed solution B, and dissolve a diamine in a NaOH aqueous solution to obtain a mixed solution C; add the mixed solution B to the white intermediate first, and then add the mixed solution C after completion, keeping the pH neutral and continuously heating to 100℃ during the addition process, and refluxing for 4-10h and recovering the catalyst triethylamine; Step five: filter the product while hot after the reaction is completed, wash the product with water, and dry to obtain the hydrazine-based triazine macromolecular charring agent.

5. The process for the preparation of hydrazine-based triazine macrochar according to claim 4, characterized in that, The monoamine in step one is a mixture of one or more of methylamine, ethylamine, propylamine, dimethylamine, and diethylamine.

6. The process for preparing hydrazine-based triazine macromolecular char formers according to claim 4, characterized in that, The molar ratio of triethylamine to cyanuric chloride is (0.01-1):

1.

7. The process for preparing hydrazine-based triazine macromolecular char formers according to claim 4, characterized in that, The molar ratio of hydrazine to diamine in step four is (0.05-1):

1.

8. The process for preparing hydrazine-based triazine macromolecular char formers according to claim 4, characterized in that, The total molar amount of hydrazine and diamine is the same as the molar amount of cyanuric chloride.

9. The process for preparing hydrazine-based triazine macromolecular char formers according to claim 4, characterized in that, The system reaction temperature is controlled below 50℃ when the mixed solution B is added in step four.

10. Use of the hydrazine-based triazine macromolecular charring agent of claim 1 in improving the flame retardation and aging resistance of high polymer materials.

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