Vinyl modified magnesium-based flame retardant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional materials, in particular to a vinyl modified magnesium-based flame retardant and a preparation method and application thereof.The preparation method comprises the following steps that hydromagnesite is added into an ethanol solution to be stirred into slurry, a modification additive is added, the temperature is increased to 50-80 DEG C, constant-temperature stirring is conducted for 10-20 min, then filtering and drying are conducted, and the vinyl modified magnesium-based flame retardant is obtained; the mass ratio of the hydromagnesite to the modification additive is 1: (0.001-0.005). The vinyl modified magnesium-based flame retardant disclosed by the invention does not contain halogen, has efficient flame retardance and good compatibility with high-molecular materials, and can improve the mechanical properties of the high-molecular polymer materials during use.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and particularly relates to a vinyl-modified magnesium-based flame retardant, a preparation method thereof, and an application thereof. Background Art

[0002] With the wide application of polymer materials in fields such as construction, electronics, and transportation, the potential safety hazards caused by their flammability have become increasingly prominent. As a key additive to improve the flame retardancy of polymer materials, the research and application of flame retardants have attracted much attention, and aluminum hydroxide and magnesium hydroxide are the most widely used. The decomposition temperature of aluminum hydroxide is low, which is suitable for polymers with processing temperatures lower than the decomposition temperature; the decomposition temperature of magnesium hydroxide is 300-330°C, which is suitable for polymers with higher processing temperatures, and it has the advantages of non-toxicity, halogen-free, smoke suppression, and environmental protection, and has become one of the most promising new flame retardants. However, magnesium hydroxide and aluminum hydroxide are expensive and have high preparation costs. Since magnesium hydroxide or aluminum hydroxide can easily cause a decrease in the mechanical properties of materials, the addition ratio is also strictly restricted. Therefore, it is necessary to develop new flame retardants to replace aluminum hydroxide and magnesium hydroxide.

[0003] Hydromagnesite is a green and environmentally friendly flame retardant that emerged after aluminum hydroxide and magnesium hydroxide, and its reserves are huge. At present, the research on hydromagnesite has gradually increased. For example, CN117844165A discloses "a method for preparing a flame retardant material and a flame retardant material", which uses an acid containing a double bond to modify hydromagnesite to obtain modified hydromagnesite; uses glycerol ester to react with the modified hydromagnesite to obtain a flame retardant substance; mixes the flame retardant substance, an antioxidant, and acrylonitrile-butadiene-styrene resin to obtain a flame retardant material, and this flame retardant material has a good flame retardant effect.

[0004] Another example is CN117089224A, which discloses "a multi-layer natural product-modified ultrafine hydromagnesite composite powder, a preparation method thereof, and an application thereof". Solution 1 is prepared by using caffeic acid, inorganic salts, and a solvent, and then hydromagnesite and a solvent are mixed to obtain dispersion liquid 2. Dispersion liquid 2 is added to solution 1 for reaction to obtain caffeic acid-modified hydromagnesite powder CA-UHM. Then, a benzeneboronic acid derivative, inorganic salts, and a solvent are mixed to obtain solution 3; the caffeic acid-modified hydromagnesite powder CA-UHM and a solvent are mixed to obtain dispersion liquid 4. Dispersion liquid 4 is dropped into solution 3 for reaction to obtain a multi-layer natural product-modified ultrafine hydromagnesite composite powder 4-TA-CA-UHM. This ultrafine hydromagnesite composite powder simultaneously realizes the synergistic flame retardant effect of the condensed phase and the gas phase, and has remarkable comprehensive flame retardant and smoke suppression effects.

[0005] However, when brucite is used as a flame retardant, due to its large polarity, its compatibility with polymer materials such as rubber is poor, and agglomeration is likely to occur, resulting in a decline in the performance of the material. Although certain modifications have been made to brucite in the above-mentioned publicly disclosed patents, the performance of the modified brucite is relatively single, which still limits its application to a certain extent.

[0006] Therefore, it is urgent to develop a halogen-free magnesium-based flame retardant with high efficiency in flame retardancy, good compatibility with polymer materials, and a wide range of applications. Summary of the Invention

[0007] The main object of the present invention is to provide a vinyl-modified magnesium-based flame retardant and a preparation method thereof. The vinyl-modified magnesium-based flame retardant is halogen-free, has high efficiency in flame retardancy, good compatibility with polymer materials, and can improve the mechanical properties and flame retardant properties of polymer materials when in use.

[0008] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0009] On the one hand, the present invention provides a preparation method of a vinyl-modified magnesium-based flame retardant, including the following steps: adding brucite into an ethanol solution and stirring to form a slurry, adding a modification assistant, heating to 50-80 °C, stirring constantly for 10-20 min, then filtering and drying to obtain the vinyl-modified magnesium-based flame retardant; the mass ratio of the brucite to the modification assistant is 1:(0.001-0.005).

[0010] Brucite has been proven to have a certain flame retardant effect, and due to its rich storage and easy availability of raw materials, it has been gradually widely used. However, due to its large polarity, brucite is prone to agglomeration in the application of polymer materials, resulting in a decline in the performance of polymer materials. In addition, it has been found through research that to achieve a high flame retardant performance, a large amount of brucite needs to be introduced to obtain an ideal flame retardant effect, but this will damage the mechanical properties and processing properties of the material.

[0011] By using brucite as the main raw material and modifying it with a modification assistant with a specific structure, the present application can solve the above technical problems. At the same time, the modified brucite can also improve the crosslinking effect with the polymer matrix and further enhance the mechanical properties of the material.

[0012] By regulating the mass ratio of the brucite to the modification assistant, the present application can prevent the modification assistant from forming a relatively thick coating layer to wrap the brucite, reducing the fluidity of the brucite and further reducing the processing performance.

[0013] In some embodiments, the modification assistant has the structure shown in Formula I below

[0014]

[0015] In this application, a modified additive with a specific structure is self-prepared. This modified additive can graft and modify with hydromagnesite well. It can not only improve the compatibility between hydromagnesite and polymer materials, but also improve the flame retardancy of hydromagnesite, increase the addition ratio of hydromagnesite without reducing the mechanical properties of the material. The reason may be that, on the one hand, the structure of the modified additive contains a large number of siloxane structures, which can react with the hydroxyl groups on the surface of hydromagnesite, so that the modified additive is anchored on the surface of hydromagnesite in the form of chemical bonds, reducing the polarity of hydromagnesite, enhancing the compatibility between hydromagnesite and the material, and preventing the decline of material properties caused by agglomeration; on the second hand, the structure of the modified additive contains a large number of N and P elements and no halogens, which can greatly improve the flame retardancy of hydromagnesite; on the third hand, the structure of the modified additive contains vinyl structures, which can carry out cross-linking reactions with the matrix resin under the irradiation cross-linking process to form a three-dimensional network structure, and can form chemical bonds at the flame retardant-matrix interface, enhancing the interfacial bonding force, thereby improving the mechanical properties.

[0016] In some embodiments, the preparation method of the modified additive includes the following steps:

[0017] S1. Mix acryloyl chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, a first solvent and azobisisobutyronitrile, heat to 60-70 °C, stir at a constant temperature for 12-14 h, filter after the reaction ends, dry, and perform column chromatography to obtain the compound shown in Formula II

[0018]

[0019] S2. Mix melamine, the compound shown in Formula II in step S1 and acryloyl chloride, add a second solvent, then add an acid-binding agent, heat to 30-40 °C and stir at a constant temperature for 6-8 h, filter after the reaction ends, extract, dry, to obtain the compound shown in Formula III

[0020]

[0021] S3. Mix the compound shown in Formula III in step S2 and chloromethyltrimethoxysilane, heat to 100-110 °C, stir at a constant temperature for 3-5 h, add diethyl ether after the reaction ends, filter, dry, to obtain the modified additive.

[0022] In some embodiments, in step S1, the molar ratio of acryloyl chloride to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(1-1.3).

[0023] Preferably, in step S1, the molar ratio of acryloyl chloride to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:1.2.

[0024] In some embodiments, in step S1, the first solvent is any one of toluene, xylene, tetrahydrofuran, and N,N-dimethylformamide.

[0025] In some embodiments, in step S2, the acid-binding agent is any one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, and triethylamine.

[0026] In some embodiments, in step S2, the molar ratio of melamine, the compound shown in formula II, and acryloyl chloride is 1:(1 - 1.2):(1 - 1.2).

[0027] Preferably, in step S2, the molar ratio of melamine, the compound shown in formula II, and acryloyl chloride is 1:1.1:1.1.

[0028] In some embodiments, the second solvent is any one of 1,4-dioxane, N,N-dimethylformamide, toluene, and chloroform.

[0029] In some embodiments, in step S3, the molar ratio of the compound shown in formula III and chloromethyltrimethoxysilane is 1:(1 - 1.4).

[0030] Preferably, in step S3, the molar ratio of the compound shown in formula III and chloromethyltrimethoxysilane is 1:1.2.

[0031] On the other hand, the present invention provides a vinyl-modified magnesium-based flame retardant prepared by the above technical solution.

[0032] On yet another aspect, the present invention provides an application of the vinyl-modified magnesium-based flame retardant in cable materials.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The vinyl-modified magnesium-based flame retardant of the present invention is prepared from hydromagnesite as a raw material through treatment with a modification assistant. This vinyl-modified magnesium-based flame retardant does not contain halogens, has high efficiency in flame retardancy, good compatibility with polymer materials, and can improve the mechanical properties of polymer materials when in use.

[0035] (2) The modifying agent of the present invention is prepared by using melamine, acryloyl chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and chloromethyltrimethoxysilane as the main synthetic raw materials. The structure of the modifying agent contains a large number of siloxane structures, which can react with the hydroxyl groups on the surface of hydromagnesite after hydrolysis, enabling the modifying agent to be anchored on the surface of hydromagnesite in the form of chemical bonds, reducing the polarity of hydromagnesite, enhancing the compatibility between hydromagnesite and the material, and preventing the decline of material properties caused by agglomeration. Secondly, the structure of the modifying agent contains a large number of N and P elements and no halogens, which can significantly improve the flame retardancy of hydromagnesite. In addition, the structure of the modifying agent contains vinyl structures, which can undergo cross-linking reactions with the matrix resin under the irradiation cross-linking process to form a three-dimensional network structure, form chemical bonds at the flame retardant-matrix interface, enhance the interfacial bonding force, and thus improve the mechanical properties. Description of the Drawings

[0036] Figure 1 1H NMR spectrum of the modifying agent in Preparation Example 1 of the present application;

[0037] Figure 2 1H NMR spectrum of the compound shown in Formula II in Preparation Example 1 of the present application;

[0038] Figure 3 1H NMR spectrum of the compound shown in Formula III in Preparation Example 1 of the present application;

[0039] Figure 4 1H NMR spectrum of the modifying agent in Preparation Example 2 of the present application;

[0040] Figure 5 1H NMR spectrum of the modifying agent in Preparation Example 3 of the present application;

[0041] Figure 6 1H NMR spectrum of the modifying agent in Preparation Example 4 of the present application. Detailed Description of the Invention

[0042] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation methods of the present invention.

[0043] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0044] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the description of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of this invention are obvious to those skilled in the art. The description and examples of this application are merely exemplary.

[0045] It should be noted that operations such as "drying", "filtering", "stirring", etc. described in this invention are conventional operations for those skilled in the art and can be selected according to actual operations.

[0046] Preparation Example 1

[0047] The preparation method of the modifying assistant includes the following steps:

[0048] S1. Mix 100 mmol of acryloyl chloride, 120 mmol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 500 mL of toluene and 0.2 g of azobisisobutyronitrile, heat up to 65 °C, stir at a constant temperature for 13 h, filter after the reaction, dry, and perform column chromatography to obtain the compound shown in Formula II

[0049]

[0050] Please refer to the atta Figure 2 chment, and the NMR analysis of the structure shown in Formula III is as follows: 1 H NMR(400MHz,)δ8.00(dd,J=8.0,1.0Hz,1H),7.92-7.84(m,2H),7.52-7.44(m,3H),7.41-7.33(m,2H),3.16-3.09(m,2H),2.75(dt,J=12.0,9.2Hz,2H);

[0051] S2. Mix 91 mmol of melamine, 100 mmol of the compound shown in Formula II in Step S1 and 100 mmol of acryloyl chloride, add 550 mL of 1,4-dioxane, then add 200 mmol of triethylamine, heat up to 35 °C and stir at a constant temperature for 7 h, filter after the reaction, extract, dry, to obtain the compound shown in Formula III

[0052]

[0053] Please refer to the atta Figure 3 chment, and the NMR analysis of the structure shown in Formula III is as follows:1 H NMR (400 MHz,) δ

[0054] 11.10 (s, 1H), 10.74 (s, 1H), 8.03 - 7.82 (m, 4H), 7.55 - 7.30 (m, 7H), 6.58 - 6.32 (m, 4H), 5.94 (ddd, J=36.0, 10.7, 3.1 Hz, 3H), 2.91 - 2.81 (m, 3H), 2.80 - 2.67 (m, 3H);

[0055] S3. Mix 100 mmol of the compound shown in Formula III in Step S2 with 120 mmol of chloromethyltrimethoxysilane, heat to 105 °C, stir at a constant temperature for 4 h. After the reaction is completed, add ether until no more precipitation occurs, filter, and dry to obtain a modified auxiliary agent with the structure shown in Formula I

[0056]

[0057] Please refer to the attached Figure 1 , and the NMR analysis of the structure shown in Formula I is as follows: 1 H NMR (400 MHz,) δ

[0058] 11.11 (s, 1H), 10.75 (s, 1H), 8.00 (dt, J=8.0, 0.6 Hz, 1H), 7.92 - 7.83 (m, 3H), 7.51 - 7.44 (m, 4H), 7.41 - 7.33 (m, 3H), 6.46 - 6.35 (m, 3H), 5.94 (ddd, J=36.0, 10.7, 3.1 Hz, 3H), 3.51 (s, 9H), 2.89 - 2.81 (m, 3H), 2.78 - 2.52 (m, 5H).

[0059] Preparation Example 2

[0060] The preparation method of the modified auxiliary agent includes the following steps:

[0061] S1. Mix 100 mmol of acryloyl chloride, 120 mmol of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, 500 mL of toluene, and 0.2 g of azobisisobutyronitrile, heat to 65 °C, stir at a constant temperature for 13 h. After the reaction is completed, filter, dry, and perform column chromatography to obtain the compound shown in Formula II

[0062]

[0063] S2. Mix 91 mmol of melamine, 100 mmol of the compound shown in Formula II in Step S1, and 200 mmol of acryloyl chloride, add 600 mL of 1,4-dioxane, then add 300 mmol of triethylamine, heat to 35 °C and stir at a constant temperature for 7 h. After the reaction is completed, filter, extract, and dry to obtain the compound shown in Formula IV, which is the modified additive.

[0064]

[0065] Please refer to the appendix Figure 4 , and the NMR analysis of the structure shown in Formula IV is as follows: 1 H NMR(400MHz,)δ

[0066] 11.11(s,1H),10.75(s,2H),8.00(dt,J=8.0,0.7Hz,1H),7.94 - 7.77(m,3H),7.59 - 7.28(m,7H),6.39(t,J=12.0Hz,2H),5.94(ddd,J=36.0,10.7,3.1Hz,5H),2.93 - 2.64(m,6H).

[0067] Preparation Example 3

[0068] The preparation method of the modified additive includes the following steps:

[0069] S1. Mix 100 mmol of melamine and 210 mmol of acryloyl chloride, add 250 mL of 1,4-dioxane, then add 260 mmol of triethylamine, heat to 35 °C and stir at a constant temperature for 7 h. After the reaction is completed, filter, extract, and dry to obtain the compound shown in Formula II.

[0070]

[0071] S2. Mix 100 mmol of the compound shown in Formula II in Step S1 and 120 mmol of chloromethyltrimethoxysilane, heat to 105 °C, and stir at a constant temperature for 4 h. After the reaction is completed, add ether until no more precipitation occurs, filter, and dry to obtain the modified additive with the structure shown in Formula V.

[0072]

[0073] Please refer to the appendix Figure 5 , and the NMR analysis of the structure shown in Formula V is as follows: 11H NMR (400 MHz, ) δ 10.75 (s, 1H), 6.47 - 6.34 (m, 6H), 5.94 (ddd, J = 36.0, 10.7, 3.1 Hz, 8H), 3.51 (s, 14H), 2.70 - 2.52 (m, 4H).

[0074] Preparation Example 4

[0075] The preparation method of the modifying auxiliary agent comprises the following steps:

[0076] S1. Mix 100 mmol of acryloyl chloride, 120 mmol of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, 500 mL of toluene and 0.2 g of azobisisobutyronitrile, heat up to 65 °C, stir at a constant temperature for 13 h, filter after the reaction ends, dry, and perform column chromatography to obtain the compound shown in Formula II

[0077]

[0078] S2. Add 91 mmol of melamine and 100 mmol of the compound shown in Formula II in Step S1 to 400 mL of 1,4 - dioxane, then add 100 mmol of triethylamine, heat up to 35 °C and stir at a constant temperature for 7 h, filter after the reaction ends, extract, dry, to obtain the compound shown in Formula VI

[0079]

[0080] S3. Mix 100 mmol of the compound shown in Formula VI in Step S2 and 120 mmol of chloromethyltrimethoxysilane, heat up to 105 °C, stir at a constant temperature for 4 h, add ether until no more precipitation occurs after the reaction ends, filter, dry, to obtain the modifying auxiliary agent with the structure shown in Formula VII

[0081]

[0082] Please refer to the attachment Figure 6 , and the NMR analysis of the structure shown in Formula VII is as follows: 1 1H NMR (400 MHz, ) δ

[0083] 11.06 (s, 1H), 8.02 - 7.98 (m, 1H), 7.91 - 7.84 (m, 3H), 7.51 - 7.45 (m, 4H), 7.40 - 7.33 (m, 2H), 6.63 - 6.51 (m, 3H), 6.38 (t, J = 8.0 Hz, 2H), 3.51 (s, 9H), 2.90 - 2.81 (m, 3H), 2.78 - 2.53 (m, 5H).

[0084] Example 1

[0085] A preparation method of a vinyl-modified magnesium-based flame retardant, comprising the following steps: adding 10 g of hydromagnesite to 200 mL of a 95 wt% ethanol solution, stirring to form a slurry, adding 0.03 g of a modification aid, heating to 65 °C, stirring at a constant temperature for 15 min, then filtering and drying to obtain the vinyl-modified magnesium-based flame retardant.

[0086] Among them, the modification aid is prepared from Preparation Example 1.

[0087] Example 2

[0088] A preparation method of a vinyl-modified magnesium-based flame retardant, comprising the following steps: adding 10 g of hydromagnesite to 200 mL of a 93 wt% ethanol solution, stirring to form a slurry, adding 0.01 g of a modification aid, heating to 50 °C, stirring at a constant temperature for 20 min, then filtering and drying to obtain the vinyl-modified magnesium-based flame retardant.

[0089] Among them, the modification aid is prepared from Preparation Example 1.

[0090] Example 3

[0091] A preparation method of a vinyl-modified magnesium-based flame retardant, comprising the following steps: adding 10 g of hydromagnesite to 200 mL of a 97 wt% ethanol solution, stirring to form a slurry, adding 0.05 g of a modification aid, heating to 80 °C, stirring at a constant temperature for 10 min, then filtering and drying to obtain the vinyl-modified magnesium-based flame retardant.

[0092] Among them, the modification aid is prepared from Preparation Example 1.

[0093] Example 4

[0094] A preparation method of a vinyl-modified magnesium-based flame retardant, the specific implementation manner is the same as that of Example 1, the difference is that the modification aid is prepared from Preparation Example 2.

[0095] Example 5

[0096] A preparation method of a vinyl-modified magnesium-based flame retardant, the specific implementation manner is the same as that of Example 1, the difference is that the modification aid is prepared from Preparation Example 3.

[0097] Example 6

[0098] A preparation method of a vinyl-modified magnesium-based flame retardant, the specific implementation manner is the same as that of Example 1, the difference is that the modification aid is prepared from Preparation Example 4.

[0099] Comparative Example 1

[0100] A preparation method of a vinyl-modified magnesium-based flame retardant, the specific implementation method is the same as that of Example 1, except that the mass of the modification assistant is 0.1 g.

[0101] Performance test:

[0102] (1) Contact angle test: Press the vinyl-modified magnesium-based flame retardant into a sheet sample with dimensions of 2 cm × 2 cm × 1 cm, and perform the contact angle test on it using the sessile drop method;

[0103] (2) Activation index: Refer to the standard of T / CSTM 01202-2024 "Test Method for Activation Index of Organically Modified Inorganic Powder Materials" for testing. The higher the activation index, the stronger the hydrophobic property.

[0104] Test the vinyl-modified magnesium-based flame retardants of each example and comparative example according to the above test methods, and the test results are shown in Table 1.

[0105] Table 1

[0106] Contact Angle (°) Activation Index (%) Example 1 107.6 96 Example 2 105.2 94 Example 3 108.1 96 Example 4 93.8 90 Example 5 90.3 95 Example 6 106.1 97 Comparative Example 1 106.9 94

[0107] According to the data analysis in Table 1, it can be seen that the vinyl-modified magnesium-based flame retardants prepared in Examples 1 to 3 and Example 6 have good hydrophobic properties and high activation indices, improving the compatibility between the vinyl-modified magnesium-based flame retardant and the polymer matrix; compared with Example 1, in Example 4, due to the change in the molar ratio of melamine, the compound shown in Formula II, and acryloyl chloride, and the silicon-oxygen structure was not introduced, resulting in a decrease in the activation index and contact angle of the vinyl-modified magnesium-based flame retardant; in Example 5, since the modification assistant structure does not contain a phenyl structure, the hydrophobic groups in the modification assistant structure are reduced, thus reducing the hydrophobic property of the vinyl-modified magnesium-based flame retardant and resulting in a decrease in the contact angle of the vinyl-modified magnesium-based flame retardant; in Comparative Example 1, due to the change in the mass ratio of hydromagnesite and the modification assistant, although the performance change is not obvious, the actual operation is very difficult due to the decrease in fluidity, and the applicable range is restricted.

[0108] Mix 10 g of POE 7467, 10 g of EVA 2803A, and 0.4 g of antioxidant 1010, and then mix them with 15 g of the vinyl-modified magnesium-based flame retardant and 15 g of hydromagnesite in each example respectively. The sample mixed with hydromagnesite is used as the control group. Using 60Co-γ as the radiation source with an intensity of 3.7×10 15 Bq, irradiate at an irradiation dose rate of 10 kGy / h for 5 h in an N2 atmosphere, granulate, and then place at room temperature for 24 h to obtain the cable material masterbatch.

[0109] (3) Oxygen index: Refer to GB / T2408-2008 to test the flame retardant performance of the cable material masterbatch;

[0110] (4) Tensile strength: Refer to the standard of GB / T 1040-1992 to test the tensile strength of the cable compound masterbatch.

[0111] Test the cable compound masterbatch according to the above test method, and the test results are shown in Table 2.

[0112] Table 2

[0113] Oxygen Index (%) Tensile Strength (MPa) Control Group 23.7 8.1 Example 1 34.6 15.9 Example 2 32.1 14.0 Example 3 35.7 15.2 Example 4 33.7 19.6 Example 5 27.1 18.8 Example 6 33.8 8.6

[0114] According to the data analysis in Table 2, it can be seen that the cable compound masterbatch prepared with the vinyl-modified magnesium-based flame retardant in Examples 1 to 4 has good flame retardancy and tensile properties; in Example 5, due to the absence of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, the P element is lacking in the vinyl-modified magnesium-based flame retardant, and the effect of multi-element synergistic flame retardancy cannot be achieved, resulting in a decrease in the flame retardancy of the cable compound masterbatch. However, due to the increase in the content of vinyl groups, its tensile properties are improved; in Example 6, since the structure of the vinyl-modified magnesium-based flame retardant does not contain vinyl groups, a cross-linked structure cannot be formed with the matrix, resulting in a decrease in the tensile properties of the cable compound masterbatch.

[0115] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a vinyl-modified magnesium-based flame retardant, characterized in that: The method comprises the following steps: adding hydromagnesite to an ethanol solution and stirring the mixture into a slurry, adding a modification auxiliary agent, heating the mixture to 50-80°C, stirring the mixture at a constant temperature for 10-20 minutes, filtering the mixture, and drying the mixture to obtain a vinyl-modified magnesium-based flame retardant; the mass ratio of the hydromagnesite to the modification auxiliary agent is 1:(0.001-0.005).

2. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 1, characterized in that: The modification aid has the structure shown in the following formula I 3. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 2, characterized in that: The preparation method of the modified auxiliary agent comprises the following steps: S1. Mix acryloyl chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, the first solvent and azobisisobutyronitrile, raise the temperature to 60-70°C, and stir at constant temperature for 12-14 hours. After the reaction is completed, filter, dry, and perform column chromatography to obtain a compound shown in Formula II. S2, mixing melamine, the compound represented by formula II in step S1 and acryloyl chloride, adding a second solvent, then adding an acid binding agent, heating to 30-40°C and stirring at a constant temperature for 6-8h, filtering after the reaction, extracting, and drying to obtain a compound represented by formula III S3. Mix the compound represented by formula III in step S2 and chloromethyltrimethoxysilane, raise the temperature to 100-110° C., and stir at the constant temperature for 3-5 hours. After the reaction is completed, add ether, filter, and dry to obtain a modification aid.

4. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 3, characterized in that: In step S1, the molar ratio of acryloyl chloride to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(1-1.3).

5. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 3, characterized in that: In step S2, the acid binding agent is any one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and triethylamine.

6. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 3, characterized in that: In step S2, the molar ratio of melamine, the compound represented by formula II and acryloyl chloride is 1:(1-1.2):(1-1.2).

7. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 3, characterized in that: The second solvent is any one of 1,4-dioxane, N,N-dimethylformamide, toluene and chloroform.

8. The method for preparing the vinyl-modified magnesium-based flame retardant according to claim 3, characterized in that: In step S3, the molar ratio of the compound represented by formula III to chloromethyltrimethoxysilane is 1:(1-1.4).

9. A vinyl-modified magnesium-based flame retardant prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the vinyl-modified magnesium-based flame retardant according to claim 9 in cable materials.

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