Bimodal compounds based on the DOPS-triazinetrione structure, their preparation methods and applications

Abstract

This invention provides a bimolecular compound based on a DOPS-triazine trione structure, its preparation method, and its applications, relating to the field of flame retardant materials technology. The bimolecular compound contains a triazine trione group and a DOPS group, with the triazine trione group and the DOPS group connected by a bridging bond structure. This bimolecular compound has advantages such as high flame retardant efficiency, low dosage, and halogen-free environmental friendliness. Adding it as a flame retardant to polymer substrates not only imparts excellent flame retardant properties to the polymer material but also helps maintain its good mechanical properties. It can be widely used in polymer substrates such as epoxy resins, polyesters, and polyolefins.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, and in particular to a bibasic compound based on the DOPS-triazine trione structure, its preparation method, and its application. Background Technology

[0002] Phosphaphenanthrene flame retardants have been extensively studied due to their environmental friendliness, high carbon content, good compatibility, and long-lasting flame retardancy. Utilizing the reactive nature of the PH bond in the molecular structure of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), it can undergo addition reactions with various unsaturated groups, resulting in the preparation of phosphaphenanthrene derivative flame retardant molecules with different structures.

[0003] According to literature reports, some studies have modified the structure of DOPO by replacing P=O with P=S, resulting in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide (DOPS). Existing research indicates that: First, sulfur, as a flame-retardant element, enhances the flame-retardant effect of phosphorus when introduced into the structure of DOPO. Sulfur-containing compounds can release strong acids such as H2SO4 at high temperatures, promoting dehydration and char formation of the substrate, thus exhibiting excellent flame-retardant properties even in the condensed phase. Second, sulfur helps suppress the dripping behavior of flame-retardant modified substrates. Third, the introduction of sulfur into the DOPO structure increases the reactivity of the PH bond, making it easier for DOPS to undergo addition reactions with unsaturated groups, facilitating the formation of various DOPS derivatives.

[0004] Triazine trione derivatives have a six-membered ring structure with alternating nitrogen atoms and carbonyl groups forming the basic skeleton. The nitrogen atoms on the triazine trione ring can be extended into a variety of chemically reactive branched structures, thereby further preparing a series of triazine trione derivatives.

[0005] Therefore, by molecular design, we can study and develop a method to link triazine trione groups and DOPS groups in the same flame retardant molecule through different bridging structures, thereby obtaining flame retardant materials with excellent performance through the synergistic effect of the two groups and constructing a new and efficient flame retardant system, which has good application prospects.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a bimolecular compound based on the DOPS-triazine trione structure, specifically three bimolecular compounds based on the DOPS-triazine trione structure, namely, bimolecular compounds with structures of formulas (II), (III), and (IV). These three compounds all possess advantages such as high flame retardant efficiency, low dosage, and halogen-free environmental friendliness. Adding them as flame retardants to polymer substrates not only imparts excellent flame retardant properties to the polymer materials but also helps maintain their good mechanical properties.

[0008] The second objective of this invention is to provide a method for preparing a bibasic compound based on the DOPS-triazine trione structure. This method has the advantages of being easy to operate, simple to implement, having relatively mild reaction conditions, and allowing for solvent recycling.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] This invention provides a bimolecular compound based on the DOPS-triazinetrione structure, wherein the bimolecular compound contains a triazinetrione group and a DOPS group;

[0011] The triazine trione group and the DOPS group in the dibasic compound are connected by a bridging bond structure.

[0012] Furthermore, the structure of the DOPS group is shown in formula (Ⅰ):

[0013]

[0014] Note: The DOPS group is a group containing the DOPS structure as shown in structural formula (Ⅰ), and DOPS is an abbreviation for 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide.

[0015] Furthermore, the structure of the dibasic compound is shown in formula (II):

[0016]

[0017] Furthermore, the structure of the dibase compound is shown in formula (Ⅲ):

[0018]

[0019] Furthermore, the structure of the dibasic compound is shown in formula (Ⅳ):

[0020]

[0021] The present invention provides a method for preparing a bimolecular compound based on the above-mentioned DOPS-triazine trione structure, wherein the preparation method mainly involves an addition reaction between DOPS and a triazine trione compound;

[0022] The triazine triones include one of triallyl isocyanurate (TAIC), tris(2-acryloyloxyethyl) isocyanurate (TEAIC), or tris(2-hydroxyethyl) isocyanurate (THEIC).

[0023] Furthermore, the dibasic compound of formula (II) is mainly prepared by DOPS and triallyl isocyanurate (TAIC);

[0024] Preferably, the method for preparing the dibasic compound with the structure of formula (II) includes:

[0025] (a) First, heat DOPS to melt, then add triallyl isocyanurate (TAIC) to DOPS in batches, stir and mix well, and heat. The two raw materials undergo an addition reaction in the molten state.

[0026] (b) After cooling the product from step (a) to room temperature, add an organic solvent for washing multiple times. The organic solvent can be ethyl acetate or dichloromethane.

[0027] (c) The solid product after washing with organic solvent in step (b) is dried under vacuum to obtain a dibasic compound with the structure of formula (II).

[0028] Furthermore, the dibasic compound of formula (III) is mainly prepared by DOPS and tris(2-acryloyloxyethyl)isocyanurate (TEAIC);

[0029] Preferably, the method for preparing the dibasic compound with the structure of formula (Ⅲ) includes:

[0030] (d) Add reaction solvent to DOPS and tris(2-acryloyloxyethyl) isocyanurate (TEAIC) respectively, and after dissolution, slowly add the tris(2-acryloyloxyethyl) isocyanurate (TEAIC) solution to DOPS solution, stir and mix, heat, and all raw materials undergo addition reaction in reaction solvent;

[0031] (e) Let the product from step (d) stand and cool to room temperature, then add distilled water for washing multiple times.

[0032] (f) The product washed in step (e) is heated and dried under vacuum to finally obtain a dibasic compound with the structure of formula (Ⅲ).

[0033] Furthermore, the dibasic compound of formula (Ⅳ) is mainly prepared from DOPS, maleic anhydride (MAH) and tris(2-hydroxyethyl) isocyanurate (THEIC);

[0034] Preferably, the method for preparing the dibasic compound with the structure of formula (Ⅳ) includes:

[0035] (g) Add an organic solvent to maleic anhydride (MAH) and tris(2-hydroxyethyl) isocyanurate (THEIC), dissolve, stir and mix well, protect with nitrogen, heat and react for a period of time.

[0036] (h) Slowly add DOPS solution to the reaction system of step (g) in batches, stir and mix well, heat, and all raw materials undergo addition reaction in the reaction solvent;

[0037] (i) Let the product from step (h) stand and cool to room temperature, then add distilled water for washing multiple times.

[0038] (j) The product washed in step (i) is heated and dried under vacuum to finally obtain a dibasic compound with the structure of formula (Ⅳ).

[0039] The present invention provides an application of the above-described DOPS-triazine trione-based bimolecular compound as a flame retardant in a polymer substrate.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] In this invention, DOPS (phosphaphenanthrene) and triazine trione groups are introduced into the same flame retardant molecule. The triazine trione group is used to improve the flame retardant efficiency of the DOPS group. The two have a synergistic flame retardant effect and can be widely used in epoxy resin, polyester, polyolefin and other substrates to obtain flame retardant composite materials with good comprehensive performance to meet the needs of different fields.

[0042] The dual-base compound flame retardant provided by this invention has high flame retardant efficiency, requires a small amount, and is halogen-free, which is beneficial to environmental protection.

[0043] The dual-base compound flame retardant provided by this invention has readily available raw materials, is simple to operate, has mild reaction conditions, and the solvent can be recycled.

[0044] The three novel bibasic compound flame retardants provided by this invention can not only be used to study the synergistic mechanism of phosphaphenanthrene and triazine trione bibasic compounds, but also enrich and expand the variety and application scope of bibasic flame retardants based on the DOPS-triazine trione structure, providing a reference for the development of novel and efficient flame retardants. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 The infrared spectrum of the dibasic compound II provided in Example 1 of this invention;

[0047] Figure 2 The 1H NMR spectrum of the dibase compound II provided in Example 1 of this invention;

[0048] Figure 3 The phosphorus NMR spectrum of the dibasic compound II provided in Example 1 of this invention;

[0049] Figure 4 The infrared spectrum of the dibasic compound III provided in Example 3 of this invention;

[0050] Figure 5 The 1H NMR spectrum of the dibase compound III provided in Example 3 of this invention;

[0051] Figure 6 The phosphorus NMR spectrum of the dibasic compound III provided in Example 3 of this invention;

[0052] Figure 7 The infrared spectrum of the dibasic compound IV provided in Example 5 of this invention;

[0053] Figure 8 The 1H NMR spectrum of the dibase compound IV provided in Example 5 of this invention;

[0054] Figure 9 The phosphorus NMR spectrum of the dibasic compound IV provided in Example 5 of this invention. Detailed Implementation

[0055] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] According to one aspect of the present invention, a bimolecular compound based on a DOPS-triazine trione structure, said bimolecular compound containing a triazine trione group and a DOPS group;

[0057] The triazine trione group and the DOPS group in the dibasic compound are connected by a bridging bond structure.

[0058] Furthermore, the structure of the DOPS group is shown in formula (Ⅰ):

[0059]

[0060] Furthermore, the structure of the dibasic compound is shown in formula (II):

[0061]

[0062] Furthermore, the structure of the dibase compound is shown in formula (Ⅲ):

[0063]

[0064] Furthermore, the structure of the dibasic compound is shown in formula (Ⅳ):

[0065]

[0066] The above-mentioned bi-base compounds based on the DOPS-triazine trione structure provided by this invention overcome the shortcomings of single-group flame retardants, such as large addition amounts and low flame retardant efficiency, and improve the compatibility between flame retardants and substrates. The bi-base compound flame retardants of this invention not only have high flame retardant efficiency, small addition amounts, low smoke, and low toxicity, but also possess excellent processing properties, resulting in flame-retardant composite materials with good overall performance.

[0067] It should also be noted that the DOPS group in compound II promotes char formation of the substrate, and the triazine trione group, as a carbon source, enhances the flame-retardant effect of compound II in the condensed phase. In the gas phase, the phosphorus-containing free radicals generated by the cracking of the DOPS group have a free radical quenching effect, and the non-flammable gas generated by the thermal cracking of the triazine trione group has a dilution effect. Therefore, compound II plays a synergistic flame-retardant role in both the condensed and gas phases. The CO2 generated by the cracking of the ester group in the bridging structure of compound III at high temperature, together with the nitrogen-containing inert gas released by the thermal cracking of the triazine trione group, dilutes the O2 around the substrate and effectively reduces the heat on the substrate surface. The phosphorus-containing free radicals generated by the cracking of the DOPS group also play a free radical quenching role, interrupting the combustion reaction. Therefore, compound III mainly plays a flame-retardant role in the gas phase. Compound IV forms more ester chain segments inside the material through the esterification reaction of carboxyl and hydroxyl groups, thereby increasing the crosslinking degree of the composite material and resulting in a more continuous and dense char layer. Therefore, compound IV mainly plays a flame-retardant role in the condensed phase.

[0068] According to one aspect of the present invention, a method for preparing a bimolecular compound based on the above-described DOPS-triazine trione structure is provided, wherein the preparation method mainly involves an addition reaction between DOPS and a triazine trione compound;

[0069] The triazine triones include one of triallyl isocyanurate (TAIC), tris(2-acryloyloxyethyl) isocyanurate (TEAIC), or tris(2-hydroxyethyl) isocyanurate (THEIC).

[0070] In a preferred embodiment of the present invention, the dibase compound II is prepared from triallyl isocyanurate (TAIC) and DOPS.

[0071] The specific reaction process is as follows:

[0072]

[0073] In the preferred embodiment described above, during the preparation of compound II, TAIC and DOPS are used as raw materials, and the synthesis is carried out by melt synthesis at a reaction temperature of 120-150°C and a reaction time of 1-8 hours.

[0074] In the above preferred embodiment, the product is washed 2-6 times, the washing solvent is ethyl acetate (or dichloromethane), and the drying is carried out in a vacuum drying oven at a temperature of 40-60°C for 4-8 hours.

[0075] In a preferred embodiment of the present invention, the dibase compound III is prepared from tris(2-acryloyloxyethyl)isocyanurate (TEAIC) and DOPS.

[0076] The specific reaction process is as follows:

[0077]

[0078] In the above preferred embodiment, during the preparation of compound III, TEAIC and DOPS are used as raw materials to carry out a substitution reaction. The reaction solvent is dioxane, the catalyst is triethylamine, the reaction temperature is 70-100℃, and the reaction time is 12-30h.

[0079] In the above preferred embodiment, the product is washed 2-6 times, the washing solvent is distilled water, and the drying is carried out in a vacuum drying oven at a temperature of 60-120°C for 6-8 hours.

[0080] In the preferred embodiment described above, during the preparation of compound III, the molar ratio of raw materials DOPS and TEAIC is (0.9-10):1.

[0081] In the preferred embodiment described above, the reaction solvent includes any one or a mixture of several of ethanol, toluene, xylene, chlorobenzene, tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide, and its amount is 10-20 times the mass of the DOPS.

[0082] In a preferred embodiment of the present invention, the bibase compound IV is prepared from maleic anhydride (MAH), tris(2-hydroxyethyl) isocyanurate (THEIC) and DOPS.

[0083] The specific reaction process is as follows:

[0084]

[0085] In the preferred embodiment described above, during the preparation of compound IV, THEIC and MAH are used as raw materials, dioxane is used as the reaction solvent, the reaction temperature is 80-120°C, and the reaction time is 1-8 hours.

[0086] In the preferred embodiment described above, a dioxane solution of DOPS is slowly added to the solution after the first step reaction, the reaction temperature is 100-130°C, and the reaction time is 5-18 hours.

[0087] In the preferred embodiment described above, the product obtained from the reaction is sequentially washed and vacuum dried.

[0088] In the above preferred embodiment, the product is washed 2-6 times, the washing solvent is distilled water, and the drying is carried out in a vacuum drying oven at a temperature of 60-120°C for 4-8 hours.

[0089] In the preferred embodiment described above, during the preparation of compound IV, the molar ratio of the raw materials DOPS, MAH, and THEIC is (3-6):(3-6):1.

[0090] In the preferred embodiment described above, the reaction solvent includes any one or a mixture of several of ethanol, toluene, xylene, chlorobenzene and tetrahydrofuran, and its amount is 10-20 times the mass of the DOPS.

[0091] According to one aspect of the present invention, the use of a bimolecular compound based on the above-described DOPS-triazine trione structure as a flame retardant in a polymer substrate.

[0092] The DOPS-triazine trione-based bimolecular compounds provided by this invention can be widely used as flame retardants in polymer substrates, specifically in epoxy resins, polyesters, polyolefins, and other polymer substrates. These DOPS-triazine trione-based bimolecular compounds, as flame retardants, not only improve the flame retardant properties of materials but also help maintain the good mechanical properties of polymer materials.

[0093] Example 1

[0094] Preparation of compound II:

[0095] (1) Weigh DOPS and TAIC in a molar ratio of 4:1;

[0096] (2) Add the weighed DOPS to a three-necked flask equipped with a thermometer, condenser, and stirrer, and heat to 100°C. Then add the weighed TAIC to the above reaction system within 1 hour. After the addition is complete, heat to 140°C and continue the reaction for 2 hours.

[0097] (3) After the above reaction was completed, the reaction system was cooled to room temperature, washed three times with ethyl acetate, and dried under vacuum at 60°C for 6 hours. Finally, compound II was obtained as a white glassy solid with a melting point of 164.4-165.3°C, a yield of 92.5%, and a purity of >99.0%.

[0098] Figure 1 The infrared spectrum of the dibasic compound II obtained in this embodiment;

[0099] Figure 2 The above is the 1H NMR spectrum of the dibase compound II prepared in this embodiment;

[0100] Figure 3 This is the phosphorus NMR spectrum of the dibasic compound II obtained in this embodiment.

[0101] Example 2

[0102] Preparation of compound II:

[0103] The specific operating steps are the same as in Example 1, except that DOPS and TAIC are weighed in a molar ratio of 3:1. Finally, compound II is obtained as a white glassy solid with a melting point of 164.4-165.3℃, a yield of 95%, and a purity of >99.0%.

[0104] Example 3

[0105] Preparation of Compound III:

[0106] (1) Weigh DOPS and TEAIC in a molar ratio of 4:1;

[0107] (2) Use the organic solvent dioxane as the reaction medium to ensure that the reactants can react fully;

[0108] (3) Add the weighed DOPS to a three-necked flask equipped with a thermometer, condenser, and stirrer. Add an appropriate amount of solvent and triethylamine catalyst. Install a reflux condenser and heat to 85°C. Then add an appropriate amount of solvent to the weighed TEAIC. After it is completely dissolved, add it dropwise to the above reaction system within 1 hour. After the addition is complete, continue the reflux reaction for 20 hours.

[0109] (4) After the above reaction is completed, the product is washed with distilled water 5 times and then dried under vacuum at 100°C for 8 hours. The final product is a white powder solid with a melting point of 105.7-106.3°C, a yield of 80%, and a purity of >99.0%.

[0110] Figure 4 The infrared spectrum of the dibasic compound III obtained in this embodiment;

[0111] Figure 5 The 1H NMR spectrum of the dibase compound III prepared in this embodiment;

[0112] Figure 6 This is the phosphorus NMR spectrum of the dibasic compound III prepared in this embodiment.

[0113] Example 4

[0114] Preparation of Compound III:

[0115] The specific operating steps are the same as in Example 3, except that DOPS and TEAIC are weighed in a molar ratio of 3:1. The final product is a white powder solid with a yield of 83% and a purity of >99.0%.

[0116] Example 5

[0117] Preparation of compound IV:

[0118] (1) Weigh THEIC and MAH in a molar ratio of 1:3;

[0119] (2) Use the organic solvent dioxane as the reaction medium to ensure that the reactants can react fully;

[0120] (3) Add the weighed THEIC and MAH to a three-necked flask equipped with a thermometer, condenser and stirrer, add an appropriate amount of solvent, install a reflux condenser, heat to 95°C and react for 2 hours.

[0121] (4) Then add an appropriate amount of solvent to the weighed DOPS. After it is completely dissolved, add it dropwise to the above reaction system within 1 hour. After the addition is complete, raise the temperature to 110°C and continue to reflux for 8 hours.

[0122] The mass ratio of DOPS, MAH and THEIC in the preparation process is 3:3:1;

[0123] (5) After the above reaction is completed, the product is washed 5 times with distilled water and dried under vacuum at 100°C for 8 hours. The final product is a white powder solid with a melting point of 214.7-215.2°C, a yield of 74%, and a purity of >99.0%.

[0124] Figure 7 The infrared spectrum of the dibasic compound IV obtained in this embodiment;

[0125] Figure 8 The above is the 1H NMR spectrum of the dibase compound IV prepared in this embodiment;

[0126] Figure 9 This is the phosphorus NMR spectrum of the dibasic compound IV obtained in this embodiment.

[0127] Example 6

[0128] Preparation of compound IV:

[0129] The specific operating steps are the same as in Example 5, except that DOPS, MAH and TEAIC are weighed in a molar ratio of 3:4:1. The final product is a white powder solid with a yield of 78% and a purity of >99.0%.

[0130] Experimental Example 1

[0131] The bi-base compounds containing the DOPS-triazine trione structure prepared in the various embodiments of the present invention were added to epoxy resin as flame retardants, and their effects on the flame retardant properties and mechanical properties of epoxy resin were investigated.

[0132] Specifically: In this experimental example, the epoxy resin used in each experimental group was: brand E51, Hunan Yueyang Baling Petrochemical Co., Ltd.

[0133] Experimental Group 1: Epoxy resin composite material, which, by mass parts, includes 87.5 parts epoxy resin and 12.5 parts of the double-base compound prepared in Example 1. The processing temperature of the mixture is 160-180°C.

[0134] After taking the components according to the above-mentioned weight proportions, prepare the epoxy resin composite material according to the following steps:

[0135] (1) Dry the epoxy resin and the double-base compound obtained in Example 1 at 80-85°C for 4-6 hours;

[0136] (2) The dried double-base compound obtained in Example 1 is then mixed with epoxy resin to obtain a blend.

[0137] (3) Finally, the blend obtained in step (2) is cured to obtain a flame-retardant epoxy resin composite material.

[0138] Experimental Group 2: This experimental group is the same as Experimental Group 1 except that the "double-base compound prepared in Example 1" is replaced with "double-base compound prepared in Example 3". The other parts are 90 parts epoxy resin and 10 parts double-base compound prepared in Example 3.

[0139] Experimental Group 3: This experimental group is the same as Experimental Group 1 except that “the bibasic compound prepared in Example 1” is replaced with “the bibasic compound prepared in Example 5”.

[0140] Comparative Experiment 1: Pure epoxy resin substrate was treated using the same method as in Experiment 1 (100 parts of epoxy resin were used in Comparative Example 1 without the addition of the double-base compound prepared in Example 1).

[0141] The flame retardant and mechanical properties of the epoxy resin composite materials prepared in the different experimental groups are as follows:

[0142]

[0143] As shown in the table above, the addition of the DOPS-triazinetrione structured double-base flame retardant in this invention can effectively improve the flame retardant properties of epoxy resin. Furthermore, because the flame retardant can be uniformly dispersed in the epoxy resin, it does not lead to a significant reduction in the mechanical properties of the epoxy resin. Specifically, when the addition amounts of flame retardants DOPS-TAIC, DOPS-TEAIC, and DOPS-THEIC are 12.5%, 10.0%, and 12.5%, respectively, all three flame-retardant epoxy resin composites achieve the UL-94V-0 rating and maintain good mechanical properties.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Application of a bimolecular compound based on the DOPS-triazinetrione structure as a flame retardant in a polymer matrix; The bimolecular compound based on the DOPS-triazine trione structure is shown in the following structural formula (IV); Formula (Ⅳ); The dual-base compound based on the DOPS-triazinetrione structure is used as a reactive flame retardant in epoxy resin, enabling the epoxy resin to achieve a UL-94 V-0 flame retardant rating while maintaining a flexural strength of 155.16 MPa.

2. The application according to claim 1, characterized in that, The bibasic compound of formula (Ⅳ) is mainly prepared from DOPS, maleic anhydride and tris(2-hydroxyethyl) isocyanurate.

3. The application according to claim 2, characterized in that, The method for preparing the dibasic compound with the structure of formula (Ⅳ) includes: (g) Add an organic solvent to tris(2-hydroxyethyl) isocyanurate and maleic anhydride, dissolve and stir to mix, and heat under nitrogen protection for a period of time. (h) Add DOPS solution to the reaction system of step (g), stir and mix well, heat, and all raw materials undergo addition reaction in the reaction solvent; (i) Let the product from step (h) stand and cool to room temperature, then wash with distilled water; (j) The product washed in step (i) is heated and dried under vacuum to finally obtain a dibasic compound with the structure of formula (Ⅳ).

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