Halogen-free flame retardant TCPA as well as preparation method and application thereof

Abstract

The invention discloses a halogen-free flame retardant TCPA and a preparation method and application thereof.The preparation method comprises the steps that phosphoric acid tri (2-chloropropyl) ester and piperazine monomers react in an alkaline environment to obtain the halogen-free flame retardant TCPA, and then orthophosphoric acid and the piperazine monomers are subjected to a polymerization reaction to prepare piperazine phosphate. The halogen-free flame retardant TCPA disclosed by the invention has relatively excellent flame retardant property and good thermal stability; and the flame-retardant polymer composite material can be prepared with a polymer, the mechanical property is improved, and the initial decomposition temperature and carbon residue of a matrix are improved, so that the thermal stability of the matrix is improved.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to a halogen-free flame retardant TCPA, its preparation method, and its application. Background Technology

[0002] The flammability of polymer materials and the accompanying dripping problem during combustion severely restrict their application in many fields with high safety requirements. Improving flame retardancy and suppressing dripping are core requirements for enhancing the safety level of polymers. Adding flame retardants is the main means to achieve this goal, but it faces a dual dilemma: on the one hand, halogenated flame retardants are facing elimination due to environmental pressures, and halogen-free alternatives need to meet the requirements of high-efficiency flame retardancy; on the other hand, the introduction of traditional flame retardants often comes at the cost of sacrificing the mechanical properties of polymers (such as toughness and strength), and their effect on suppressing dripping is limited. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, this invention provides a halogen-free flame retardant TCPA, its preparation method, and its applications. The halogen-free flame retardant TCPA of this invention is prepared by polymerization of tris(2-chloropropyl) phosphate and piperazine monomers. Its use in preparing flame-retardant polymers not only improves the flame-retardant properties of the matrix polymer but also avoids secondary damage caused by melt dripping during combustion and imparts other excellent properties to the matrix, such as good thermal stability and excellent mechanical properties.

[0004] The technical solution of the present invention is as follows: The first objective of this invention is to provide a halogen-free flame retardant TCPA having the structure shown in the following general formula (1):

[0005] General formula (1) R1-R4 are independently represented by one or more of H, carboxyl, carbonyl, methylene alcohol, cyclohexyl, methyl, cyanomethyl, and aminomethyl. The molecular weight of the halogen-free flame retardant TCPA is 1000–5000 g / mol.

[0006] In one embodiment of the present invention, the halogen-free flame retardant TCPA has the following structure: .

[0007] A second objective of this invention is to provide a method for preparing the above-mentioned halogen-free flame retardant TCPA, comprising the following steps: (1) Dissolve tris(2-chloropropyl) phosphate (TCPP) in an organic solvent to obtain a tris(2-chloropropyl) phosphate solution; (2) Dissolve piperazine monomers in an organic solvent to prepare an organic solution containing piperazine monomers; (3) An organic solution containing piperazine monomer (PAPZ) was added dropwise to a tri(2-chloropropyl) phosphate solution at 0-5℃. After reacting for a period of time, the temperature was raised and the reaction was stopped. After the reaction was completed, the temperature was lowered to 0-5℃. (4) Add an organic solution containing phosphoric acid dropwise, and simultaneously add triethylamine. Keep the pH of the reaction system at 6.5-7.5. After reacting for a period of time, extract, wash and dry to obtain the halogen-free flame retardant TCPA.

[0008] In one embodiment of the present invention, in step (2), the piperazine monomer has the structure shown in general formula (2):

[0009] General formula (2) R1-R4 are independently represented by one or more of H, carboxyl, carbonyl, methylene alcohol, cyclohexyl, methyl, cyanomethyl, and aminomethyl.

[0010] In one embodiment of the present invention, in step (1), tris(2-chloropropyl) phosphate has the following structure: .

[0011] In one embodiment of the present invention, the piperazine monomer has the structure shown in any of the following structures: , , , , , , , .

[0012] In one embodiment of the present invention, in steps (1) and (2), the organic solvent is one or more of dichloromethane, trichloromethane, tetrahydrofuran, and aqueous ethanol solution.

[0013] In one embodiment of the present invention, in step (1), the concentration of the tri(2-chloropropyl) phosphate solution is 0.1 mol / 100 mL.

[0014] In one embodiment of the present invention, in step (2), the concentration of piperazine monomer in the organic solution containing piperazine monomer is 0.3 mol / 100 mL.

[0015] In one embodiment of the present invention, in step (3), the molar ratio of tris(2-chloropropyl) phosphate to piperazine monomer is 1:3-5.

[0016] In one embodiment of the present invention, in step (3), the reaction conditions are: stirring at 0-5°C for 3-5 hours, then raising the temperature to 25-30°C, and stirring for another 5-8 hours.

[0017] In one embodiment of the present invention, in step (4), the organic solution containing phosphoric acid is an organic solution containing orthophosphoric acid or polyphosphoric acid, and the concentration is prepared to be 10-20 wt%.

[0018] In one embodiment of the present invention, in step (4), the reaction conditions are: maintaining the pH of the system at 6.5-7.5 with triethylamine, the temperature at 20-25°C, and the time at 3-5 h.

[0019] In one embodiment of the present invention, half a volume of an organic solution containing a piperazine monomer is added dropwise to a tri(2-chloropropyl) phosphate solution at 0-5°C, and triethylamine is added dropwise to ensure that the pH of the system is 7.5-8.5, and the optimal reaction time is 4-5 hours.

[0020] In one embodiment of the present invention, the temperature is raised to 25°C, and half a volume of organic solution containing piperazine monomers is added dropwise again, with an optimal reaction time of 5-8 hours.

[0021] In one embodiment of the present invention, an organic solution of orthophosphoric acid is added dropwise, and triethylamine is added dropwise simultaneously, maintaining the pH of the reaction system at 6.5-7.5, and the optimal reaction time is 3-5 hours.

[0022] A third objective of this invention is to provide a flame-retardant polymer containing the above-mentioned halogen-free flame retardant TCPA, wherein the content of halogen-free flame retardant TCPA is 6-8 wt%.

[0023] In one embodiment of the present invention, the raw material composition of the flame retardant polymer is as follows: by weight, the raw materials are 92-94 parts of polymer material and 6-8 parts of the above-mentioned halogen-free flame retardant TCPA.

[0024] In one embodiment of the present invention, the polymeric material is at least one selected from polylactide, polylactic acid, polyethylene, polypropylene, and polyethylene terephthalate.

[0025] The fourth objective of this invention is to provide an application of the above-mentioned halogen-free flame retardant TCPA or the above-mentioned flame retardant polymer in the fields of medical device manufacturing, textiles, construction or transportation.

[0026] The beneficial technical effects of this invention are as follows: The halogen-free flame retardant TCPA of this invention has excellent flame retardant properties and good thermal stability. Moreover, when exerting its flame retardant effect, it delays the dripping of the melt, greatly reducing secondary damage from fire and smoke, thus providing better fire safety.

[0027] The flame-retardant polymer composite material of the present invention exhibits superior mechanical properties and thermal stability. The halogen-free flame retardant TCPA and the polymer preparation method of the present invention can increase the initial decomposition temperature and char residue of the matrix, thereby improving the thermal stability of the substrate and enhancing the mechanical properties of the composite material. Attached Figure Description

[0028] Figure 1 The 1H NMR spectrum of TCPA, the halogen-free flame retardant obtained in Example 1; Figure 2 The thermogravimetric analysis curves obtained in the example are shown. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] The raw materials and their sources used in the embodiments of the present invention are as follows: Polylactide, sourced from TotalCoppen Energy, model number LX575.

[0031] Example 1 (1) Dissolve 0.1 mol of tris(2-chloropropyl) phosphate (TCPP) in 100 mL of dichloromethane to obtain a tris(2-chloropropyl) phosphate dichloromethane solution; dissolve 0.3 mol of piperazine monomer in 100 mL of dichloromethane to prepare a dichloromethane solution containing piperazine monomer; add the dichloromethane solution containing piperazine monomer dropwise to the tris(2-chloropropyl) phosphate dichloromethane solution at 0 °C, while simultaneously adding triethylamine, maintaining the pH of the reaction system at 7.5-8.5, reacting for 3 h, then raising the system temperature to 25 °C and reacting for 5 h; add 50 mL of 20 A solution of wt% phosphoric acid in dichloromethane was prepared, and triethylamine was added dropwise. The pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed and extracted with excess water-carrying agent. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times and finally dried in a vacuum oven at 60°C for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this context, R1, R2, R3, and R4 are all hydrogen atoms.

[0032] (2) 6 parts by mass of halogen-free flame retardant TCPA and 94 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0033] Example 2 (1) Dissolve 0.1 mol of tris(2-chloropropyl) phosphate (TCPP) in 100 mL of dichloromethane to obtain a tris(2-chloropropyl) phosphate dichloromethane solution; dissolve 0.3 mol of piperazine monomer in 100 mL of dichloromethane to prepare a dichloromethane solution containing piperazine monomer; add the dichloromethane solution containing piperazine monomer dropwise to the tris(2-chloropropyl) phosphate dichloromethane solution at 0 °C, while simultaneously adding triethylamine, maintaining the pH of the reaction system at 7.5-8.5, reacting for 3 h, then raising the system temperature to 25 °C and reacting for 5 h; add 50 mL of 20 A solution of wt% phosphoric acid in dichloromethane was prepared, and triethylamine was added dropwise. The pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed and extracted with excess water-carrying agent. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times and finally dried in a vacuum oven at 60°C for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this case, R1 = CH2CN, and R2, R3 and R4 are all hydrogen atoms.

[0034] (2) 6 parts by mass of halogen-free flame retardant TCPA and 94 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame retardant polymer composite material was obtained by compression molding.

[0035] Example 3 (1) Dissolve 0.1 mol of tris(2-chloropropyl) phosphate (TCPP) in 100 mL of dichloromethane to obtain a tris(2-chloropropyl) phosphate dichloromethane solution; dissolve 0.3 mol of piperazine monomer in 100 mL of dichloromethane to prepare a dichloromethane solution containing piperazine monomer; add the dichloromethane solution containing piperazine monomer dropwise to the tris(2-chloropropyl) phosphate dichloromethane solution at 0 °C, while simultaneously adding triethylamine, maintaining the pH of the reaction system at 7.5-8.5, reacting for 3 h, then raising the system temperature to 25 °C and reacting for 5 h; add 50 mL of 20 A solution of wt% phosphoric acid in dichloromethane was prepared, and triethylamine was added dropwise. The pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed and extracted with excess water-carrying agent. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times and finally dried in a vacuum oven at 60°C for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this context, R1, R2, R3, and R4 are all hydrogen atoms.

[0036] (2) Eight parts by mass of halogen-free flame retardant TCPA and 92 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0037] Example 4 (1) Dissolve 0.1 mol of tris(2-chloropropyl) phosphate (TCPP) in 100 mL of dichloromethane to obtain a tris(2-chloropropyl) phosphate dichloromethane solution; dissolve 0.3 mol of piperazine monomer in 100 mL of dichloromethane to prepare a dichloromethane solution containing piperazine monomer; add the dichloromethane solution containing piperazine monomer dropwise to the tris(2-chloropropyl) phosphate dichloromethane solution at 0 °C, while simultaneously adding triethylamine, maintaining the pH of the reaction system at 7.5-8.5, reacting for 3 h, then raising the system temperature to 25 °C and reacting for 5 h; add 50 mL of 20 A solution of wt% phosphoric acid in dichloromethane was prepared, and triethylamine was added dropwise. The pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed and extracted with excess water-carrying agent. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times and finally dried in a vacuum oven at 60°C for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this case, R1 = CH2CN, and R2, R3 and R4 are all hydrogen atoms.

[0038] (2) Eight parts by mass of halogen-free flame retardant TCPA and 92 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0039] Example 5 (1) First, 0.1 mol tris(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 50 mL of dichloromethane solution containing 0.3 mol piperazine monomer was added dropwise to the above system at 0℃, and triethylamine was added dropwise at the same time to maintain the pH of the reaction system at 7.5-8.5. After reacting for 4 hours, the temperature was raised to 25℃, and 50 mL of dichloromethane solution containing 0.3 mol piperazine monomer was added dropwise, and triethylamine was added dropwise to maintain the pH of the reaction system at 7.5-8.5. After reacting for 5 hours, 50 mL of dichloromethane solution of 20 wt% orthophosphoric acid was added dropwise, and triethylamine was added dropwise to maintain the pH of the reaction system at 6.5-7.5. After reacting for 3 hours, the solution was removed, and excess water-carrying agent was added for extraction. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times. Finally, it was dried in a vacuum oven at 60℃ for 12 hours to obtain halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this context, R1, R2, R3, and R4 are all hydrogen atoms.

[0040] (2) 6 parts by mass of halogen-free flame retardant TCPA and 94 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0041] Example 6 (1) First, 0.1 mol tris(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise to the above system at 0℃, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for 4 hours, the temperature was raised to 25℃, and another 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for another 5 hours, 50 mL of a dichloromethane solution containing 20 wt% orthophosphoric acid was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed, and excess water-carrying agent was added for extraction, resulting in a white precipitate. The precipitate was then washed with deionized water 5-8 times, and finally dried in a vacuum oven at 60℃ for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this case, R1 = CH2CN, and R2, R3 and R4 are all hydrogen atoms.

[0042] (2) 6 parts by mass of halogen-free flame retardant TCPA and 94 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame retardant polymer composite material was obtained by compression molding.

[0043] Example 7 (1) First, 0.1 mol tris(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise to the above system at 0℃, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for 4 hours, the temperature was raised to 25℃, and another 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for another 5 hours, 50 mL of a dichloromethane solution containing 20 wt% orthophosphoric acid was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed, and excess water-carrying agent was added for extraction, resulting in a white precipitate. The precipitate was then washed with deionized water 5-8 times, and finally dried in a vacuum oven at 60℃ for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this context, R1, R2, R3, and R4 are all hydrogen atoms.

[0044] (2) Eight parts by mass of halogen-free flame retardant TCPA and 92 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding. Example 8 (1) First, 0.1 mol tris(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise to the above system at 0℃, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for 4 hours, the temperature was raised to 25℃, and another 50 mL of a dichloromethane solution containing 0.3 mol piperazine monomers was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 7.5-8.5. After reacting for another 5 hours, 50 mL of a dichloromethane solution containing 20 wt% orthophosphoric acid was added dropwise, while triethylamine was added dropwise, and the pH of the reaction system was maintained at 6.5-7.5. After reacting for 3 hours, the solution was removed, and excess water-carrying agent was added for extraction, resulting in a white precipitate. The precipitate was then washed with deionized water 5-8 times, and finally dried in a vacuum oven at 60℃ for 12 hours to obtain the halogen-free flame retardant TCPA. The structural formula of piperazine monomers is In this case, R1 = CH2CN, and R2, R3 and R4 are all hydrogen atoms.

[0045] (2) Eight parts by mass of halogen-free flame retardant TCPA and 92 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0046] Test example: The flame retardant TCPA prepared in Example 1 was subjected to... 1 H NMR characterization, results as follows Figure 1 As shown in the figure, the chemical shift (δ) shows an absorption peak for -CH3 at 0.94–0.98, absorption peaks for -CH2- at 3.44–3.46 and 2.41–2.43, and an absorption peak for -CH- at 2.49–2.53. 1 The results of 1H NMR confirmed the successful synthesis of the halogen-free flame retardant TCPA. The molecular weight and thermal stability data of the flame retardant TCPA are shown in Table 1 below.

[0047] Table 1

[0048] To investigate the flame retardancy, non-dripping properties, heat resistance, and mechanical properties of the flame-retardant polymer prepared by the method of the present invention, the samples obtained in Examples 3-8 were tested.

[0049] The flame retardant properties of the obtained flame-retardant polymers were tested using the limiting oxygen index (LOI) experiment, and the results are shown in Table 2. The specific testing method is as follows: According to GB / T 2406.2-2009, the material was cut into 90×10×4mm strips for testing. If the strip extinguishes within 3 minutes at a certain oxygen content (oxygen volume percentage) and does not burn to within 5cm below the ignition point, then the oxygen content should be increased until either of the above two conditions cannot be met. This critical value is the limiting oxygen index (LOI) of the strip. When the oxygen index (LOI) is less than 22%, the material is considered flammable; when the oxygen index (LOI) is between 22% and 27%, the material is considered combustible; when the oxygen index (LOI) is greater than 27%, the material is considered flame-retardant. The material was subjected to vertical burning (UL-94) testing according to ASTM D3801 standard. The sample dimensions were 100 × 12 × 3 mm. 3 .

[0050] Table 2

[0051] The mechanical properties of the obtained flame-retardant polymers were tested using a universal tensile testing machine in accordance with standard GB / T 1040-2006. The tensile rate was 30 mm / min, and each group of samples was tested 5 times and the average value was calculated. The results are shown in Table 3.

[0052] Table 3

[0053] The thermal decomposition behavior of the obtained flame-retardant polymer was tested using a thermogravimetric analyzer (TGA / DSC / 1100SF). Approximately 10 mg of sample was weighed and placed in a crucible. Under a nitrogen atmosphere, the temperature was increased from 40 °C to 800 °C at a rate of 20 °C / min, with a nitrogen flow rate of 50 mL / min. The thermal stability data of the flame-retardant polymer composites prepared in the examples are shown in Table 4 below.

[0054] Table 4

[0055] As shown in Tables 2-4, the prepared flame-retardant polymer has the following advantages: 1) Excellent flame-retardant and drip-suppressing properties, with limiting oxygen indices all above 28%, meeting the standards for flame-retardant materials; 2) Good mechanical properties, with tensile strength maintaining its original good performance, and some examples showing a slight enhancement effect; 3) High thermal stability and high char residue. Therefore, the flame-retardant polymer obtained by this invention can be used in daily necessities, office supplies, transportation equipment, the construction industry, and light industry.

[0056] Comparative Example 1 Compared with Example 1, the structure of the amino-containing monomer was changed while other conditions remained the same, as follows: (1) First, 0.1 mol of tri(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 100 mL of dichloroform solution containing 0.3 mol of p-phenylenediamine was added dropwise to the above system at 0℃, while triethylamine was added dropwise. The pH of the reaction system was kept at 7.5-8.5. After reacting for 3 h, the temperature was raised to 25℃ and the reaction was continued for 5 h. Then, 50 mL of 20 wt% dichloroform solution of orthophosphoric acid was added dropwise, while triethylamine was added dropwise. The pH of the reaction system was kept at 6.5-7.5. After reacting for 3 h, the system was taken out and extracted with excess water-carrying agent. A white precipitate was precipitated. The precipitate was washed with deionized water 5-8 times. Finally, it was dried in a vacuum oven at 60℃ for 12 h to obtain the halogen-free flame retardant TCPD. The structural formula of p-phenylenediamine is .

[0057] (2) 6 parts by mass of halogen-free flame retardant TCPA-3 and 94 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0058] Comparative Example 2 Compared with Example 3, the structure of the amino-containing monomer was changed while other conditions remained the same, as follows: (1) First, 0.1 mol tris(2-chloropropyl) phosphate (TCPP) was dissolved in 100 mL of chloroform. Then, 50 mL of dichloromethane solution containing 0.3 mol piperazine monomer was added dropwise to the above system at 0℃, and triethylamine was added dropwise at the same time to maintain the pH of the reaction system at 7.5-8.5. After reacting for 4 hours, the temperature was raised to 25℃, and 50 mL of dichloromethane solution containing 0.3 mol piperazine monomer was added dropwise, and triethylamine was added dropwise to maintain the pH of the reaction system at 7.5-8.5. After reacting for 5 hours, 50 mL of dichloromethane solution of 20 wt% orthophosphoric acid was added dropwise, and triethylamine was added dropwise to maintain the pH of the reaction system at 6.5-7.5. After reacting for 3 hours, the solution was removed, and excess water-carrying agent was added for extraction. A white precipitate was precipitated. The precipitate was then washed with deionized water 5-8 times. Finally, it was dried in a vacuum oven at 60℃ for 12 hours to obtain halogen-free flame retardant TCPA. The structural formula of p-phenylenediamine is .

[0059] (2) Eight parts by mass of halogen-free flame retardant TCPA-3 and 92 parts by mass of polylactide were melt-blended at 180°C using a torque rheometer, and then the flame-retardant polymer composite material was obtained by compression molding.

[0060] The flame-retardant polymers in the comparative examples were measured using the same method mentioned in Example 1. The results are shown in Table 5.

[0061] Table 5

[0062] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A halogen-free flame retardant TCPA, characterized in that, has the following general formula (1) structure: General formula (1) R1-R4 are independently represented as H, carboxyl, carbonyl, methylene alcohol, cyclohexyl, methyl, cyanomethyl, aminomethyl, one or more of which; The molecular weight of the halogen-free flame retardant TCPA is 1000-5000 g / mol.

2. The halogen-free flame retardant TCPA according to claim 1, characterized in that, has the following structure: 。 3. A process for the preparation of the halogen-free flame retardant TCPA according to claim 1, characterized in that, The preparation method comprises the following steps: (1) Dissolve tri (2-chloropropyl) phosphate in an organic solvent to obtain a tri (2-chloropropyl) phosphate solution; (2) Dissolve the piperazine monomer in an organic solvent to obtain an organic solution containing the piperazine monomer; (3) At 0-5℃, add the organic solution containing the piperazine monomer to the tri (2-chloropropyl) phosphate solution dropwise, react for a period of time, then warm up the reaction, and cool down to 0-5℃ after the reaction is completed; (4) Further add an organic solution containing phosphoric acid, and add triethylamine dropwise, keep the pH of the reaction system at 7.5-8.5, react for a period of time, then extract, wash, and dry to obtain the halogen-free flame retardant TCPA.

4. The production method according to claim 3, characterized by, In step (2), the piperazine monomer has the following general formula (2) structure: General formula (2) R1-R4 are independently represented as H, carboxyl, carbonyl, methylene alcohol, cyclohexyl, methyl, cyanomethyl, aminomethyl, one or more of which.

5. The preparation method according to claim 4, characterized in that, The structure of the piperazine monomer is shown in any one of the following structures: 、 、 、 、 、 、 、 。 6. The preparation method according to claim 3, characterized in that, In steps (1) and (2), the organic solvent is one or more of dichloromethane, trichloromethane, tetrahydrofuran, and an ethanol aqueous solution.

7. The production method according to claim 3, characterized by, In step (3), the molar ratio of tri (2-chloropropyl) phosphate to the piperazine monomer is 1:3-5; the reaction conditions are: stirring at 0-5℃ for 3-5 h, then warming up to 25-30℃, and stirring for 5-8 h.

8. The production method according to claim 3, characterized by, In step (4), the organic solution containing phosphoric acid is an organic solution of orthophosphoric acid or polyphosphoric acid, and the concentration is 10-20 wt%; the reaction conditions are: keeping the pH of the system at 6.5-7.5 with triethylamine, the temperature is 20-25℃, and the time is 5-8 h.

9. A flame retardant polymer containing the halogen-free flame retardant TCPA according to claim 1, characterized in that, The content of the halogen-free flame retardant is 6-8 wt%.

10. Use of the halogen-free flame retardant TCPA of claim 1 or the flame-retardant polymer of claim 9 in the preparation of medical devices, textiles, construction, or transportation.

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