Trinity cyclophosphazene-based flame retardant as well as preparation method and application thereof

Abstract

The invention discloses a trinity cyclophosphazene-based flame retardant, which belongs to the technical field of chemical materials, and the structural formula of the flame retardant is as follows: # imgabs 0 # and # imgabs 1 #, the preparation method of the flame retardant comprises the following specific steps: uniformly mixing a pentaerythritol solution and a melamine solution, sequentially dropwise adding an acid-binding agent and a phosphonitrilic chloride trimer solution, and reacting to obtain a precipitate, namely the trinity cyclophosphazene-based flame retardant. According to the invention, a substance containing a triazine ring and a hydroxyl structure with high carbon content and phosphonitrilic chloride trimer are subjected to nucleophilic substitution reaction, and through a molecular design integrating gas source-carbon source-acid source, the existence of a benzene ring, a nitrogen element and a carbon element is beneficial to improving the flame retardant efficiency of the phosphonitrilic chloride trimer; the high efficiency of element collection of the phosphazene derivative in the combustion process of a high polymer material is favorably improved, so that the purpose of condensed phase-gas phase dual flame retardance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical materials, and particularly relates to a trinity cyclophosphazene-based flame retardant, a preparation method thereof and an application thereof. Background Art

[0002] With the development of society and the improvement of industrial level, all walks of life pay more and more attention to the combustion safety of building materials and products. Therefore, there are an endless stream of flame retardants on the market. However, the existing flame retardants in the current prior art have problems such as instability, excessive dosage and insecurity.

[0003] At present, in order to achieve an ideal flame retardant effect, a relatively large amount of flame retardant usually needs to be added, which will cause a significant decline in the mechanical properties of the material. At the same time, due to the easy agglomeration of the flame retardant in the material matrix and the poor compatibility with the material matrix, phenomena such as uneven dispersion, easy migration to the surface of the matrix and poor thermal stability of the flame retardant in the material matrix will occur, affecting the flame retardant performance of the material.

[0004] Phosphazene is a kind of compound formed by alternating phosphorus and nitrogen elements, with a stable phosphorus-nitrogen backbone structure. Its unique phosphorus-nitrogen hybrid structure and high phosphorus and nitrogen content endow it with good thermal stability and flame retardancy. Phosphazene has the advantages of being halogen-free, having less smoke generation during combustion, high flame retardancy efficiency, and not generating toxic and corrosive gases, and is considered to be the second-generation phosphorus-nitrogen-based intumescent flame retardant. Since the synthesis of phosphazene compounds, they have experienced more than a hundred years of research and development. They are applied in a wide range of fields such as military materials in the United States, and there are also application researches in various fields in China, especially in the field of flame retardancy. However, the market-oriented phosphazene flame retardants in China are limited, mainly due to problems in aspects such as flame retardancy efficiency and element synergistic effect of the existing nitrogen-phosphorus-based flame retardants.

[0005] Therefore, it is an urgent problem for those skilled in the art to provide a stable, non-excessive addition amount, safe and efficient phosphorus-based flame retardant. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a trinity cyclophosphazene-based flame retardant, a preparation method thereof and an application thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A trinity cyclophosphazene-based flame retardant, the structure of the flame retardant is selected from any one of the following:

[0009] 、 。

[0010] According to the above-mentioned preparation method of a trinity cyclophosphazene-based flame retardant, it includes the following specific steps:

[0011] After mixing the pentaerythritol solution and the melamine solution evenly, a deacidifying agent and a hexachlorocyclotriphosphazene solution are successively added dropwise for reaction. After the reaction ends, the precipitate obtained is a trinity cyclophosphazene-based flame retardant.

[0012] Preferably, the molar ratio of the hexachlorocyclotriphosphazene, the melamine, the pentaerythritol and the deacidifying agent is 2:2 - 4:1:12.

[0013] Preferably, the molar ratio of the hexachlorocyclotriphosphazene, the melamine, the pentaerythritol and the deacidifying agent is 2:4:1:12.

[0014] Preferably, the molar ratio of the hexachlorocyclotriphosphazene, the melamine, the pentaerythritol and the deacidifying agent is 1:1:2:6.

[0015] Preferably, the deacidifying agent is triethylamine.

[0016] Preferably, the solvents of the pentaerythritol solution, the melamine solution and the hexachlorocyclotriphosphazene solution are N,N-dimethylformamide or dimethyl sulfoxide, and the addition amount only needs to ensure that the hexachlorocyclotriphosphazene, the melamine and the pentaerythritol can be dissolved.

[0017] Preferably, the temperature of the reaction is 25 - 80 °C and the time is 12 - 48 h.

[0018] Preferably, the reaction is carried out under a nitrogen atmosphere.

[0019] Preferably, the process route of the preparation method is:

[0020]

[0021] Or

[0022] .

[0023] The application of the flame retardant prepared according to the above-mentioned preparation method or the above-mentioned flame retardant in the preparation of epoxy resin.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) In the present invention, a substance containing a triazine ring and a hydroxyl structure with a high carbon content undergoes a nucleophilic substitution reaction with hexachlorocyclotriphosphazene. Through a molecular design that integrates "gas source - carbon source - acid source", the presence of benzene rings, nitrogen elements and carbon elements is beneficial to improving the flame retardant efficiency of cyclophosphazene, and helps to improve the efficiency of element aggregation of phosphazene derivatives during the combustion of polymer materials, thereby achieving the purpose of double flame retardancy in the condensed phase - gas phase.

[0026] (2) The product prepared by the present invention is used as a flame retardant additive for polymer materials, and has the properties of good heat resistance, good synergistic effect, relatively rich flame retardant element content, and high flame retardant efficiency;

[0027] (3) The preparation method and post-treatment method of the present invention are simple, the reagents used are non-toxic and have no potential environmental pollution hazards, and the raw materials do not require pretreatment, greatly reducing the economic and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0029] Figure 1 It is the infrared spectrogram of the flame retardant in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] Example 1

[0032] A preparation method of a trinity cyclophosphazene-based flame retardant, comprising the following specific steps:

[0033] (1) Dissolve 3.4766 g of hexachlorocyclotriphosphazene and 0.68075 g of pentaerythritol in 30 ml of N,N-dimethylformamide respectively, and disperse and dissolve 2.5224 g of melamine in 140 ml of N,N-dimethylformamide. Among them, the dissolution is carried out under ultrasonic conditions with a power of 100 w. Then, mix the pentaerythritol solution and the melamine solution evenly and dropwise add 8 ml of triethylamine solution. The triethylamine solution is dropped at a rate of about 1 drop per second and is added dropwise within about 3 minutes. After the addition is completed, the reaction system is under a nitrogen atmosphere, and the hexachlorocyclotriphosphazene solution is slowly added dropwise. The hexachlorocyclotriphosphazene is added dropwise at a rate of 1-2 drops per second and is added dropwise within 10 minutes. After the addition is completed, take good gas tightness measures to make the reaction proceed under nitrogen protection. React at 25 °C for 48 h. The whole reaction process is under ultrasonic conditions with a power of 100 w. During the reaction process, it should be ensured that there is sufficient clear water in the ultrasonic instrument;

[0034] (2) After the reaction is completed, cool and let stand, perform vacuum filtration, collect the solid material with anhydrous ethanol three times to obtain an off-white solid, and dry it in a vacuum at 70 °C to obtain the trinity cyclophosphazene-based flame retardant with the structure of , with a yield of 90% and a purity of about 85%.

[0035] Example 2

[0036] A preparation method of a trinity cyclophosphazene-based flame retardant includes the following specific steps:

[0037] (1) Dissolve 3.4766 g of hexachlorocyclotriphosphazene and 2.723 g of pentaerythritol completely with 30 ml and 90 ml of N,N-dimethylformamide respectively, and disperse and dissolve 1.2612 g of melamine with 70 ml of N,N-dimethylformamide. Among them, the dissolution is carried out under ultrasonic conditions with a power of 100 w. Then mix the pentaerythritol solution and the melamine solution evenly and dropwise add 8 ml of triethylamine solution. The triethylamine solution is dropped at a rate of about 1 drop per second and is added dropwise within about 3 min. After the addition is completed, the reaction system is under a nitrogen atmosphere, and the hexachlorocyclotriphosphazene solution is slowly added dropwise. The hexachlorocyclotriphosphazene is added dropwise at a rate of 1-2 drops per second and is added dropwise within 10 min. After the addition is completed, take good gas tightness measures to make the reaction proceed under nitrogen protection. React at 25 °C for 48 h. The whole reaction process is under ultrasonic conditions with a power of 100 w. During the reaction process, it should be ensured that there is sufficient clear water in the ultrasonic instrument;

[0038] (2) After the reaction is completed, cool and let stand, perform vacuum filtration, collect the solid material with anhydrous ethanol twice to obtain an off-white solid, and dry it in a vacuum at 70 °C to obtain the trinity cyclophosphazene-based flame retardant with the structure of , with a yield of 40% and a purity of about 85%.

[0039] Example 3

[0040] A preparation method of a trinity cyclophosphazene-based flame retardant includes the following specific steps:

[0041] (1) Dissolve 3.4766 g of hexachlorocyclotriphosphazene and 0.68075 g of pentaerythritol separately in 30 ml of dimethyl sulfoxide. Dissolve 2.5224 g of melamine in 100 ml of dimethyl sulfoxide by sufficient dispersion. Among them, the dissolutions are all carried out under the ultrasonic condition with a power of 100 w. Then mix the pentaerythritol solution and the melamine solution evenly and dropwise add 8 ml of triethylamine solution. The triethylamine solution is dropped at a speed of about 1 drop per second and is added dropwise within about 3 minutes. After the addition is completed, the reaction system is under a nitrogen atmosphere, and the hexachlorocyclotriphosphazene solution is slowly added dropwise. The hexachlorocyclotriphosphazene is added dropwise at a speed of 1 - 2 drops per second and is added dropwise within 10 minutes. After the addition is completed, take good gas tightness measures to make the reaction proceed under nitrogen protection. React at 25 °C for 48 h. The whole reaction process is under the ultrasonic condition with a power of 100 w. During the reaction process, it should be ensured that there is sufficient clear water in the ultrasonic instrument;

[0042] (2) After the reaction is completed, cool and let it stand, carry out vacuum filtration, wash the collected solid substance with anhydrous ethanol three times to obtain an off-white solid, and dry it in vacuum at 70 °C to obtain the trinity cyclophosphazene-based flame retardant, with the structure of , the yield is 10%, and the purity is about 85%.

[0043] Example 4

[0044] A preparation method of a trinity cyclophosphazene-based flame retardant, comprising the following specific steps:

[0045] (1) Dissolve 3.4766 g of hexachlorocyclotriphosphazene and 0.68075 g of pentaerythritol separately in 30 ml of N,N-dimethylformamide. Dissolve 2.5224 g of melamine in 140 ml of N,N-dimethylformamide by sufficient dispersion. Among them, the dissolutions are all carried out under the ultrasonic condition with a power of 100 w. Then mix the pentaerythritol solution and the melamine solution evenly and dropwise add 8 ml of triethylamine solution. The triethylamine solution is dropped at a speed of about 1 drop per second and is added dropwise within about 3 minutes. After the addition is completed, the reaction system is under a nitrogen atmosphere, and the hexachlorocyclotriphosphazene solution is slowly added dropwise. The hexachlorocyclotriphosphazene is added dropwise at a speed of 1 - 2 drops per second and is added dropwise within 10 minutes. After the addition is completed, take good gas tightness measures to make the reaction proceed under nitrogen protection. React at 25 °C for 12 h. The whole reaction process is under the ultrasonic condition with a power of 100 w. During the reaction process, it should be ensured that there is sufficient clear water in the ultrasonic instrument;

[0046] (2) After the reaction is completed, cool and let it stand, carry out vacuum filtration, wash the collected solid substance with anhydrous ethanol three times to obtain an off-white solid, and dry it in vacuum at 70 °C to obtain the trinity cyclophosphazene-based flame retardant, with the structure of , the yield is 90%, and the purity is about 85%.

[0047] Such as Figure 1, which is the infrared spectrogram of the flame retardants prepared in Examples 1 and 2. As can be seen from the figure, the relevant compounds were successfully prepared.

[0048] Application Example 1

[0049] Preparation of epoxy resin composites:

[0050] The flame retardants prepared in Examples 1 and 2 were added to epoxy resin at a ratio of 1 wt%, where the epoxy resin was 30 g, and the flame retardants were 0.42 g respectively, and 12 g of curing agent DDM. After uniform mixing, it was poured into a mold and placed in an oven, cured at 100 °C for 3 h and at 160 °C for 1 h. After the curing was completed, all samples were cooled to room temperature, demolded to obtain epoxy composites, and then combustion tests were carried out.

[0051] The results of the combustion tests are shown in Table 1. The test methods are as follows: According to ASTM D3801-2006, a vertical combustion test was carried out on a vertical combustion tester to test the flammability of epoxy composites with a test size of 100×150×3 mm; according to ASTM D2863, the limiting oxygen index (LOI) of epoxy composites was tested on an oxygen index analyzer, and the sample test size was 100×150×3 mm.

[0052] The UL-94 standard is an experimental method standard for the combustion performance of materials formulated by Underwriters Laboratories in the United States, which is used to evaluate the ability of materials to extinguish after being ignited. It is stipulated that the plastic flame retardant grades increase gradually from HB, V-2, V-1 to V-0. Specifically:

[0053] HB: For samples with a thickness of 3-13 mm, the burning rate is less than 40 mm / min; for samples with a thickness less than 3 mm, the burning rate is less than 70 mm / min, or it extinguishes before the 100 mm mark.

[0054] V-2: After two 10 s combustion tests on the sample, the flame extinguishes within 10 s - 30 s, and burning debris can fall off;

[0055] V-1: After two 10 s combustion tests on the sample, the flame extinguishes within 10 s - 30 s, and no burning debris can fall off;

[0056] V-0: After two 10 s combustion tests on the sample, the flame extinguishes within 10 s, and no burning debris can fall off;

[0057] Table 1 Results of vertical combustion data of epoxy composites

[0058]

[0059] As can be seen from the data in Table 1, the flame retardancy of the epoxy composites prepared with the flame retardants in Examples 1 and 2 has reached V-0 level, and the limiting oxygen indices of the epoxy composites are 28.5% and 27.1%, respectively.

[0060] Comparative Example 1

[0061] The material is selected from: Wang Yuchong. Research on the synthesis of melamine-modified polyaminocyclotriphosphazene and its flame retardant effect on epoxy resin [D]. Qingdao University of Science and Technology, 2015.

[0062] The preparation method is as follows:

[0063] Add 10 g (0.0287 mol) of hexachlorocyclotriphosphazene, 6.95 g (0.0574 mol) of melamine, 15.67 g (0.1722 mol) of triethylamine and 200 mL of chlorobenzene into a reaction flask. Under nitrogen protection, heat and raise the temperature to 70-130 °C, react for 8-20 h, and then cool down with a salt-ice bath. Ammoniation: Wait for the temperature of the above materials to cool to -5-5 °C, and uniformly introduce ammonia gas under stirring for 8-30 h. Then filter, and after the filter cake is dried, obtain a white powdery solid - a mixture of melamine-modified aminocyclotriphosphazene and by-product water-soluble ammonium salts (triethylamine hydrochloride and ammonium chloride);

[0064] Polycondensation: Place the above mixture of melamine-modified aminocyclotriphosphazene and ammonium salts in an oven, carry out polycondensation at 170-190 °C for 10-60 min, then take it out and cool it to room temperature in the air; Separation of the polycondensation product and ammonium salts: Disperse the above-obtained polycondensation mixture into a certain amount of deionized water, stir at room temperature for 10 min, filter, wash the filter cake with a small amount of deionized water 3 times, and then dry it to constant weight to obtain melamine-modified polyaminocyclotriphosphazene (MPHACTPA);

[0065] The specific process route is as follows:

[0066] ;

[0067] Prepare a composite material of epoxy resin with the flame retardant obtained in Comparative Example 1: Mix 90 g of epoxy resin (E-44), 13.5 g of modified aliphatic amine DG731 and a certain amount of flame retardant evenly, then place it in a mold, cure at room temperature for 0.5 h, and then transfer it to a tablet press to carry out molding at room temperature to make a plate with a size of 100 mm × 100 mm × 3.2 mm. Then cut the plate into strip-shaped plates of standard size for flame retardancy testing. The influence of the addition amount of MPHACTPA-1 on the flame-retarded E-44 / DG731 is shown in Table 2;

[0068] Table 2 Vertical burning data results of epoxy composites

[0069]

[0070] As can be seen from the above table, when comparing Examples 1 and 2 with Comparative Example 1, when the mass fraction of the flame retardant in Comparative Example 1 was 20 wt%, the oxygen index of Comparative Example 1 did not exceed the relevant indicators of Examples 1 and 2. It can be seen that the products obtained by the technical solution of the present invention have better combustion indicators in epoxy resin.

[0071] Comparative Example 2

[0072] The materials were selected from: Kang Tao, Juan Li, Liang Xu, et al. A novel phosphazenecyclomatrix network polymer: Design, synthesis and application in flameretardant polylactide[J]. Polymer Degradation and Stability. 2011, 96(7):1248-1254.

[0073] The preparation method is as follows:

[0074] Put HCCP (139.06 g, 0.40 mol), PER (122.54 g, 0.60 mol), sodium hydroxide (96 g, 2.4 mol) and 300 ml of tetrahydrofuran into a 1000 ml flask, and connect a drying tube. Reflux the mixture under N2 for 6 h, then cool to room temperature, precipitate with 10 times the excess of water, filter the solid, wash with water and acetone, and dry the white product PCPP in vacuo at 80 °C to constant weight (yield 92.7%);

[0075] The specific process route is as follows:

[0076] ;

[0077] Prepare a composite material of polylactic acid using the flame retardant obtained in Comparative Example 2: All composite materials were prepared on a Brabender mixer at a temperature of 180 °C, a roll speed of 50 rpm for 8 minutes. The mixed sample was transferred to a mold, preheated at 185 °C for 5 minutes, then pressurized at 10 MPa, and cooled to room temperature while maintaining the pressure to obtain a composite material sheet for further measurement; before mixing, all materials were dried in a vacuum oven at 80 °C for at least 12 hours; the LOI and UL-94 measurement results of the PLA composite materials are shown in Table 3;

[0078] Table 3 LOI and UL-94 measurement results of PLA composite materials

[0079]

[0080] As can be seen from the above table, when comparing Examples 1 and 2 with Comparative Example 2, when the mass fraction of the flame retardant in Comparative Example 2 was 20 wt%, the oxygen index of Comparative Example 2 did not exceed the relevant indexes of Examples 1 and 2. It can be seen that the combustion indexes of the products obtained by the technical solution of the present invention in epoxy resin are better.

[0081] Each example is described in a progressive manner. The key points of each example are the differences from other examples. For the same and similar parts between each example, reference can be made to each other.

[0082] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A trinity phosphazene-based flame retardant, characterized in that, The structure of the flame retardant is selected from any one of the following: 、 。 2. The preparation method of a trinity cyclophosphazene-based flame retardant according to claim 1, wherein The specific steps include: After uniformly mixing the pentaerythritol solution and the melamine solution, a deacidifying agent and a hexachlorocyclotriphosphazene solution are successively added dropwise for reaction. After the reaction is completed, the precipitate obtained is a trinity cyclophosphazene-based flame retardant.

3. The preparation method of a trinity phosphazene-based flame retardant according to claim 2, characterized in that, The molar ratio of the hexachlorocyclotriphosphazene, the melamine, the pentaerythritol and the deacidifying agent is 2:2 - 4:1:

12.

4. The preparation method of a trinity cyclophosphazene-based flame retardant according to claim 2, characterized in that, The deacidifying agent is triethylamine.

5. The preparation method of a trinity phosphazene-based flame retardant according to claim 2, characterized in that, The solvents of the pentaerythritol solution, the melamine solution and the hexachlorocyclotriphosphazene solution are N,N-dimethylformamide or dimethyl sulfoxide.

6. The preparation method of a trinity cyclophosphazene-based flame retardant according to claim 2, characterized in that, The temperature of the reaction is 25 - 80 °C and the time is 12 - 48 h.

7. The preparation method of a trinity phosphazene-based flame retardant according to claim 2, wherein The reaction is carried out under a nitrogen atmosphere.

8. Use of the flame retardant according to claim 1 or the flame retardant prepared by the preparation method according to any one of claims 2 - 7 in the preparation of epoxy resin.

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