A melamine cyanurate flame retardant and its preparation method

Abstract

This application relates to the field of flame retardant production. More specifically, it relates to a melamine cyanurate flame retardant and its preparation method. It is prepared by the following method: 1): Weigh melamine and water and mix them evenly. After heating, add cyanuric acid, flame retardant filler, and alkali metal and mix them evenly. React until the viscosity reaches 8000-9000 mPa·s to obtain reactant A; Weigh an isocyanate group-containing crosslinking agent, polysilazane, tris(2-hydroxyethyl)isocyanurate triacrylate, alkyl acrylate phosphate, peroxide, and solvent and mix them evenly to obtain mixture B; 2): Filter reactant A to obtain a flowable white viscous substance, and then add all of it to mixture B and mix evenly. React, dry, and pulverize to obtain the melamine cyanurate flame retardant. The above process produces a melamine cyanurate flame retardant with excellent compatibility, wear resistance, high temperature resistance, mechanical properties, and flame retardancy.

Description

Technical Field

[0001] The present application relates to the field of flame retardant production, and more specifically, to a melamine cyanurate flame retardant and a preparation method thereof. Background Art

[0002] As an important environmentally friendly flame retardant material, melamine cyanurate flame retardant is widely used in multiple industries such as plastics, rubber, and coatings. Its unique molecular structure endows it with excellent flame retardant properties, which can rapidly absorb heat and generate a protective layer during a fire, effectively preventing the spread of fire and greatly improving the safety performance of materials. With the continuous improvement of society's awareness of fire safety, the demand for high-performance flame retardant materials is increasing day by day, promoting the research and development and application of melamine cyanurate flame retardant and related technologies. In recent years, with the rapid development of the industrial and construction industries, the requirements for flame retardant materials have also been continuously improved. Especially for materials that need to be used in harsh environments such as high temperature and friction, such as automotive parts and mechanical manufacturing, higher requirements are put forward for the comprehensive performance of flame retardants.

[0003] To meet these requirements, various means are usually adopted in the prior art to improve the performance of melamine cyanurate flame retardant. For example, by adding inorganic flame retardants and other methods to further improve the comprehensive performance of the flame retardant. These methods have indeed improved certain properties of the flame retardant to a certain extent, but there are still some deficiencies.

[0004] Although some progress has been made in the prior art, many challenges are still faced in practical applications. Especially in the application scenario of silicone materials, although the existing flame retardants can meet the flame retardant requirements to a certain extent, they perform poorly in terms of high-temperature aging resistance and abrasion resistance. Especially when made into silicone pad products, problems such as wear and aging are likely to occur after long-term use, seriously affecting the service life and supporting performance of the products. The existence of these problems limits the promotion and use of flame retardants in application scenarios such as automotive trim and mechanical manufacturing. Therefore, it is urgent to develop a new type of melamine cyanurate flame retardant to overcome the deficiencies in the prior art. Summary of the Invention

[0005] In order to further improve the flame retardant performance and, when applied to silicone materials, further improve the mechanical properties, wear resistance, and high-temperature resistance, the present application provides a melamine cyanurate flame retardant and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing a melamine cyanuric acid flame retardant, which is prepared by the following method: 1): according to weight parts, 5-8 parts of melamine and 10-20 parts of water are weighed and mixed evenly, and after heating, 3.5-6.8 parts of cyanuric acid, 0.3-0.8 parts of flame retardant filler, and 0.01-0.015 parts of alkali metal are added and mixed evenly, and reacted until the viscosity is 8000-9000mPa.s to obtain reactant A;

[0007] According to weight parts, 0.01-0.3 parts of an isocyanate group-containing crosslinking agent, 0.1-0.3 parts of polysilazane, 0.1-0.5 parts of tris(2-hydroxyethyl)isocyanurate triacrylate, 0.2-0.5 parts of alkyl acrylate phosphate, 0.001-0.003 parts of a peroxide, and 10-20 parts of a solvent are weighed and mixed uniformly to obtain a mixture B;

[0008] 2): The reactant A is filtered to obtain a flowable white viscous substance, which is then added to the mixture B and mixed evenly, reacted, dried, and crushed to obtain a melamine cyanuric acid flame retardant.

[0009] By adopting the above technical solution, melamine reacts with cyanuric acid under the catalytic action of alkali metal to generate melamine cyanurate with high purity. During the reaction process, flame retardant fillers are added in time to ensure that the flame retardant fillers and melamine cyanurate can be evenly dispersed. When the viscosity of the reaction system reaches 8000-9000mPa·s, melamine cyanurate presents a certain degree of semi-polymerization state, which is not only convenient for subsequent filtration treatment, but also helps to form a flowable white viscous substance, which is convenient for mixing evenly with mixture B to jointly build a more stable compound system.

[0010] As the reaction continues, the active groups in mixture B react further to form cross-linked macromolecular complexes. These complexes coat melamine cyanurate, thereby forming a melamine cyanuric acid flame retardant with a uniformly dispersed raw material system and tight molecular bonding. When the flame retardant is applied to silicone products, it can significantly improve its wear resistance, high temperature resistance, mechanical properties and flame retardant properties. Therefore, the wear and aging problems of silicone products during long-term use will be effectively reduced.

[0011] Specifically, in mixture B, a significant synergistic effect is exerted among the isocyanate group-containing crosslinking agent, tris(2-hydroxyethyl) isocyanurate triacrylate, and alkyl acrylate phosphate. When these components are combined with melamine cyanurate and flame retardant fillers, the resulting flame retardant, when applied to silicone material products, not only greatly enhances the flame retardant performance of the material but also significantly improves the high-temperature resistance, toughness, and wear resistance of the product. Ultimately, this flame retardant endows silicone material products with excellent comprehensive properties, especially suitable for scenarios such as buffer pads that require both flame retardancy and physical property requirements. On the basis of maintaining good flame retardancy, this flame retardant can significantly improve the physical properties of the material, such as reducing wear and effectively preventing aging under high-temperature environments. Therefore, the application fields of such flame retardants have been effectively broadened, providing strong support for the performance improvement and diversified applications of silicone material products.

[0012] In summary, a significant synergistic effect has occurred among the isocyanate group-containing crosslinking agent, polysilazane, tris(2-hydroxyethyl) isocyanurate triacrylate, and alkyl acrylate phosphate. This effect not only enhances the flame retardant performance and high-temperature resistance of the final product but also significantly improves its mechanical strength and wear resistance. When melamine and cyanuric acid react, a flowable white viscous substance is formed with the isocyanate group-containing crosslinking agent, polysilazane, tris(2-hydroxyethyl) isocyanurate triacrylate, and alkyl acrylate phosphate. After further compounding reaction, drying, and pulverization processes, a melamine cyanurate flame retardant with excellent compatibility, wear resistance, high-temperature resistance, mechanical properties, and flame retardant performance is obtained.

[0013] When this flame retardant is applied to the production of silicone products, it can significantly reduce the wear rate and high-temperature aging phenomenon of silicone products, thereby greatly improving their quality. In addition, the practicality of this flame retardant in fields such as automotive parts and machinery manufacturing has also been significantly enhanced, providing safer, more reliable, and durable material choices for these industries.

[0014] In addition, the melamine cyanurate flame retardant of this application is blended and modified with silicone rubber, and the resulting silicone material is applied to, but applied to fields such as automotive parts and machinery manufacturing. Specifically, in parts such as the engine compartment, chassis, and doors of automobiles, it can effectively prevent the automobile from being damaged under harsh environments such as high temperature and friction. Or it is applied in machinery manufacturing, such as wear-resistant pads in machine tools, compressors, pumps, etc., which can effectively prevent mechanical components from being damaged and aged due to friction and high temperature during long-term use.

[0015] Preferably, the flame retardant filler is composed of one or more of hydrotalcite, titanium dioxide, and antimony trioxide.

[0016] By adopting the above technical solutions, selecting one or more of hydrotalcite, titanium dioxide, and antimony trioxide as the flame retardant filler can not only effectively improve the flame retardancy efficiency of the flame retardant, but also optimize the physical properties of the final product, such as increasing the hardness, toughness, and wear resistance of the material. At the same time, it helps to improve the dispersibility of the flame retardant in the polymer matrix, ensuring that the flame retardant can achieve an efficient flame retardant effect at a lower addition amount and reducing the impact on the polymer processing performance.

[0017] Preferably, the flame retardant filler is composed of hydrotalcite and antimony trioxide in a weight ratio of 1:(1 - 3).

[0018] By adopting the above technical solutions, the flame retardant filler composed of hydrotalcite and antimony trioxide in a weight ratio of 1:(1 - 3) can effectively enhance the flame retardancy efficiency and thermal stability of the melamine cyanurate flame retardant. As a synergistic flame retardant, hydrotalcite can release carbon dioxide and water vapor at high temperatures, dilute the oxygen concentration, and inhibit flame propagation. Antimony trioxide, on the other hand, can form a protective layer during combustion, isolate oxygen contact, and at the same time promote the formation of a char layer, improving the flame retardant effect. The combination of the two improves the overall performance of the flame retardant.

[0019] Preferably, the isocyanate group-containing crosslinking agent is diisocyanate trimer and / or triallyl isocyanurate.

[0020] By adopting the above technical solutions, the diisocyanate trimer and triallyl isocyanurate act together in the flame retardant material to improve the flame retardancy performance, enhance the thermal stability, improve the comprehensive performance, and broaden the application prospects. The addition of these two components also enhances the mechanical properties of the material, especially the synergistic effect with polysilazane, tris(2-hydroxyethyl) isocyanurate triacrylate, and alkyl acrylate phosphate, effectively improving the flame retardancy, wear resistance, and high-temperature resistance of the material.

[0021] Under the catalytic action of peroxide, the active groups in the isocyanate group-containing crosslinking agent, polysilazane, tris(2-hydroxyethyl) isocyanurate triacrylate, and alkyl acrylate phosphate will further react. This reaction process promotes the formation of macromolecular crosslinked complexes, which are tightly combined with the melamine cyanurate molecules. The resulting melamine cyanurate flame retardant has a dense and stable molecular structure, thus endowing the flame retardant with excellent comprehensive performance.

[0022] Preferably, the isocyanate group-containing crosslinking agent is composed of diisocyanate trimer and / or triallyl isocyanurate in a weight ratio of 1:(0.1 - 0.3).

[0023] By adopting the above technical solution, the isocyanate group-containing crosslinking agent is composed of a diisocyanate trimer and / or triallyl isocyanurate in a specific weight ratio, which can improve the flame retardancy, enhance the thermal stability and upgrade the comprehensive performance in the flame retardant material. Specifically, this combination can enhance the mechanical properties of the material, such as increasing hardness and toughness, and generate a synergistic effect with polysilazane, tris(2-hydroxyethyl)isocyanurate triacrylate, and alkyl acrylate phosphate, further improving the flame retardancy, abrasion resistance and high temperature resistance of the material, ensuring that the material exhibits excellent comprehensive performance in practical applications.

[0024] Preferably, the polysilazane is a perhydro-inorganic polysilazane and / or an organoborosilazane.

[0025] By adopting the above technical solution, the introduction of perhydro-inorganic polysilazane and organoborosilazane not only improves the flame retardancy of the melamine cyanurate flame retardant, but also enhances its physical properties. Specifically, these two components interact with the isocyanate group-containing crosslinking agent, tris(2-hydroxyethyl)isocyanurate triacrylate, and alkyl acrylate phosphate to form an efficient synergistic effect system, making the flame retardant effect of the final product more prominent, while increasing the toughness, hardness and abrasion resistance of the material, effectively reducing problems such as wear, combustion and high temperature aging of silicone rubber products during use.

[0026] Preferably, the polysilazane is composed of perhydro-inorganic polysilazane and organoborosilazane in a weight ratio of 1:(2 - 3).

[0027] By adopting the above technical solution, the perhydro-inorganic polysilazane and organoborosilazane are mixed in a specific ratio, which not only enhances the flame retardancy of the flame retardant, but also improves the overall physical properties of the material, such as strength, hardness and abrasion resistance. This combination can also effectively improve the stability and anti-deformation ability of the material at high temperatures, especially suitable for silicone materials, which can reduce the wear and deformation of the material while maintaining a good flame retardant effect and extend the service life.

[0028] Preferably, the heating temperature in step 1) is 90 - 95 °C; the reaction temperature in step 2) is 65 - 75 °C.

[0029] By adopting the above technical solution, the heating temperature in step 1) is controlled at 90 - 95 °C, ensuring the effective reaction of melamine and cyanuric acid, promoting the formation of the target compound melamine cyanurate, and improving the purity and yield of the product. This temperature range helps to maintain an appropriate reaction rate, avoid the occurrence of side reactions, and ensure the stable quality of the product. The reaction temperature in step 2) is set at 65 - 75 °C, which helps the effective mixing and reaction among the isocyanate group-containing crosslinking agent, tris(2-hydroxyethyl)isocyanurate triacrylate, and alkyl acrylate phosphate, promotes the good compatibility and uniform distribution among the components in the final product, enhances the overall performance of the material, especially the flame retardancy and mechanical strength. The gentle heating under these conditions not only helps to maintain the activity of the materials but also prevents the degradation or deterioration of the materials caused by excessive temperature.

[0030] Preferably, the drying temperature in step 2) is 120 - 150 °C.

[0031] By adopting the above technical solution, the drying temperature is controlled within the range of 120 - 150 °C, ensuring that the melamine cyanurate flame retardant will neither degrade due to excessive temperature nor have water residue due to too low temperature during the drying process, thus ensuring the purity and performance stability of the final product. The drying treatment under this condition helps to improve the drying efficiency of the flame retardant, shorten the production cycle, and at the same time maintain the excellent flame retardant characteristics and other physical properties of the product, such as hardness, toughness, and wear resistance.

[0032] In the second aspect, a melamine cyanurate flame retardant is produced by a preparation method of a melamine cyanurate flame retardant, and the particle size of the melamine cyanurate flame retardant is less than 100 microns.

[0033] By adopting the above technical solution, the prepared melamine cyanurate flame retardant not only has excellent flame retardant performance but also can effectively improve the high-temperature resistance, toughness, hardness, and wear resistance of the material. It is especially suitable for silicone materials and can significantly reduce the problems of performance degradation and structural deformation of the material caused by abrasion, combustion, or high temperature during use. In addition, by controlling the particle size to be less than 100 microns, the dispersibility and compatibility of the flame retardant in the substrate are further improved, enhancing the comprehensive performance of the final product.

[0034] In summary, the present application includes at least one of the following beneficial technical effects:

[0035] 1. Through the mixed reaction of melamine, cyanuric acid, and flame retardant filler in a specific ratio, a melamine cyanurate complex is formed. Its viscosity is moderate, facilitating filtration and subsequent processing. Moreover, the semi-polymerized state of the unreacted melamine cyanurate complex helps to better combine with the components in mixture B, enhancing the comprehensive performance of the final product;

[0036] 2. The crosslinking agent containing isocyanate groups has a synergistic effect with tris(2-hydroxyethyl)isocyanurate triacrylate and alkyl acrylate phosphate, which not only improves the flame retardancy of the material, but also enhances the toughness, wear resistance and high temperature resistance of the material. It is especially suitable for silicone products, reducing the easy aging of the material under long-term high temperature conditions, etc.;

[0037] 3. The introduction of polysilazane realizes the effective coating of melamine cyanurate, strengthening the overall stability and physical properties of the material. It is particularly outstanding in improving the wear resistance and support performance of silicone pads, solving the problems of easy wear and deformation when traditional flame retardants are applied to silicone materials. Specific Embodiments

[0038] The following further elaborates on the present application in conjunction with examples.

[0039] Description of some raw materials:

[0040] The mesh number of the flame retardant filler is 1000 mesh;

[0041] The peroxide is benzoyl peroxide;

[0042] The perhydrogen inorganic polysilazane is preferably IOTA PHPS produced by Anhui Aiyota Silicone Oil Co., Ltd.;

[0043] The organic polyborosilazane is preferably IOTA 9120 produced by Anhui Aiyota Silicone Oil Co., Ltd.;

[0044] The alkyl acrylate phosphate is 2-hydroxyethyl methacrylate phosphate.

[0045] Examples

[0046] Example 1

[0047] A melamine cyanurate flame retardant with an average particle size of 5 microns; this melamine cyanurate flame retardant is prepared by the following method:

[0048] 1): By weight, weigh 5 parts of melamine and 10 parts of water and put them into a reaction kettle. Stir at a speed of 150 r / min for 10 min to make them fully mixed. After heating to 90 °C, add 3.5 parts of cyanuric acid, 0.8 part of flame retardant filler, and 0.01 part of alkali metal and continue to stir for 10 min to make them fully mixed. After reacting for 2 h, detect the viscosity. When the viscosity is 8000 mPa·s, stop the reaction to obtain reactant A;

[0049] Weigh 0.01 part of an isocyanate group-containing crosslinking agent, 0.3 part of polysilazane, 0.1 part of tris(2-hydroxyethyl)isocyanurate triacrylate, 0.5 part of alkyl acrylate phosphate, 0.001 part of peroxide, and 10 parts of solvent in a reaction kettle. Stir at a speed of 150 r / min for 10 min to mix them evenly to obtain mixture B.

[0050] 2): Filter the reactant A to remove water and small molecular substances to obtain a flowable white viscous substance. Then add all of it to mixture B and mix evenly. Heat to 65 °C and react for 2 h. Carry out vacuum distillation to remove the solvent, then put it in an oven at 120 °C for drying for 2 h, and then put it in a pulverizer for pulverization to obtain a melamine cyanurate flame retardant with an average particle size of 5 microns.

[0051] Among them, the flame retardant filler is antimony trioxide; the isocyanate group-containing crosslinking agent is diisocyanate trimer; the polysilazane is organopolyborosilazane.

[0052] Example 2

[0053] The difference between Example 2 and Example 1 lies in the different raw material dosages and process parameters. The melamine cyanurate flame retardant is specifically as follows:

[0054] 1): Weigh 5.3 parts of melamine and 15 parts of water in a reaction kettle. Stir at a speed of 150 r / min for 10 min to mix them evenly. After heating to 95 °C, add 4.8 parts of cyanuric acid, 0.5 part of flame retardant filler, and 0.012 part of alkali metal and continue to stir for 10 min to mix them evenly. After reacting for 2 h, detect the viscosity. When the viscosity is 8500 mPa·s, stop the reaction to obtain reactant A.

[0055] Weigh 0.1 part of an isocyanate group-containing crosslinking agent, 0.2 part of polysilazane, 0.3 part of tris(2-hydroxyethyl)isocyanurate triacrylate, 0.4 part of alkyl acrylate phosphate, 0.002 part of peroxide, and 14 parts of solvent in a reaction kettle. Stir at a speed of 150 r / min for 10 min to mix them evenly to obtain mixture B.

[0056] 2): Filter the reactant A to remove water and small molecular substances to obtain a flowable white viscous substance. Then add all of it to mixture B and mix evenly. Heat to 70 °C and react for 2 h. Carry out vacuum distillation to remove the solvent, then put it in an oven at 130 °C for drying for 2 h, and then put it in a pulverizer for pulverization to obtain a melamine cyanurate flame retardant with an average particle size of 5 microns.

[0057] Example 3

[0058] Example 3 is different from Example 1 in that the raw material dosages and process parameters are different. The melamine cyanurate flame retardant is as follows:

[0059] 1): Weigh 8 parts of melamine and 20 parts of water by weight and put them into a reaction kettle. Stir at a speed of 150 r / min for 10 min to make them fully and evenly mixed. After heating to 90 °C, add 6.8 parts of cyanuric acid, 0.3 part of flame retardant filler, and 0.015 part of alkali metal, and continue to stir for 10 min to make them fully and evenly mixed. After reacting for 2 h, detect the viscosity. When the viscosity is 9000 mPa·s, stop the reaction to obtain reactant A;

[0060] Weigh 0.3 part of isocyanate group crosslinking agent, 0.3 part of polysilazane, 0.5 part of tris(2-hydroxyethyl)isocyanurate triacrylate, 0.2 part of alkyl acrylate phosphate, 0.003 part of peroxide, and 20 parts of solvent by weight. Put them into a reaction kettle and stir at a speed of 150 r / min for 10 min to make them fully and evenly mixed to obtain mixture B;

[0061] 1.: Filter reactant A to remove water and small molecular substances to obtain a flowable white viscous substance. Then add all of it to mixture B and mix evenly. Heat to 75 °C and make it react for 2 h. Carry out vacuum distillation to remove the solvent, then put it into an oven at 150 °C for drying for 2 h, and then put it into a pulverizer for pulverization to obtain a melamine cyanurate flame retardant with an average particle size of 5 microns.

[0062] Example 4

[0063] Example 4 is different from Example 2 in that the flame retardant filler is hydrotalcite and antimony trioxide in a weight ratio of 1:3.

[0064] Example 5

[0065] Example 5 is different from Example 2 in that the isocyanate group crosslinking agent is triallyl isocyanurate.

[0066] Example 6

[0067] Example 6 is different from Example 4 in that the isocyanate group crosslinking agent is composed of diisocyanate trimer and triallyl isocyanurate in a weight ratio of 1:0.1.

[0068] Example 7

[0069] Example 7 is different from Example 4 in that the isocyanate group crosslinking agent is composed of diisocyanate trimer and triallyl isocyanurate in a weight ratio of 1:0.18.

[0070] Example 8

[0071] Example 8 is different from Example 4 in that the isocyanate group-containing crosslinking agent consists of a diisocyanate trimer and triallyl isocyanurate in a weight ratio of 1:0.3.

[0072] Example 9

[0073] Example 9 is different from Example 7 in that the polysilazane is a perhydro inorganic polysilazane.

[0074] Example 10

[0075] Example 10 is different from Example 7 in that the polysilazane consists of a perhydro inorganic polysilazane and an organic polyborosilazane in a weight ratio of 1:2.

[0076] Example 11

[0077] Example 11 is different from Example 7 in that the polysilazane consists of a perhydro inorganic polysilazane and an organic polyborosilazane in a weight ratio of 1:3.

[0078] Comparative Example

[0079] Comparative Example 1

[0080] Comparative Example 1 is different from Example 1 in that the isocyanate group-containing crosslinking agent is replaced with polysilazane in equal amounts.

[0081] Comparative Example 2

[0082] Comparative Example 2 is different from Example 1 in that the polysilazane is replaced with the isocyanate group-containing crosslinking agent in equal amounts.

[0083] Comparative Example 3

[0084] Comparative Example 3 is different from Example 1 in that the alkyl acrylate phosphate is replaced with tris(2-hydroxyethyl) isocyanurate triacrylate in equal amounts.

[0085] Comparative Example 4

[0086] Comparative Example 4 is different from Example 1 in that the tris(2-hydroxyethyl) isocyanurate triacrylate is replaced with the alkyl acrylate phosphate in equal amounts.

[0087] Comparative Example 5

[0088] Comparative Example 5 is different from Example 1 in that mixture B is replaced with reactant A in equal amounts.

[0089] Performance Detection Test

[0090] The melamine cyanurate flame retardant with an average particle size of 5 μm obtained from Examples 1-11 and Comparative Examples 1-5, vinyl silicone rubber raw rubber, and hydrogen-containing silicone oil were put into a kneader and stirred at a rotation speed of 30 rpm. While stirring, the temperature was raised at a rate of 2°C per minute. When the temperature reached 135°C, heating was stopped and it was kept warm for 1 h. Then it was cooled to 40°C and discharged to obtain a mixed rubber; the mixed rubber was put into a two-roll mixer for mixing, and a vulcanizing agent was added to mix it evenly with the vulcanizing agent to obtain a silicone material; the silicone material was put into a mold, and then the mold was put into a flat vulcanizer. It was vulcanized at 150°C for 5 min, taken out, cooled to 35°C, and demolded to obtain test samples, which were used for the following experiments.

[0091] The weight ratio of the melamine cyanurate flame retardant, vinyl silicone rubber raw rubber, hydrogen-containing silicone oil, and vulcanizing agent was 1:10:1.5:0.3.

[0092] Among them, the number-average molecular weight of the vinyl silicone rubber raw rubber was 600,000-700,000; the vinyl content was 0.15-0.18%, and the hydrogen content of the hydrogen-containing silicone oil was 0.5-1.2%; the vulcanizing agent was bis(2,5-dimethyl-2,5-di(t-butylperoxy)hexane).

[0093] Reference specimen: The above-mentioned melamine cyanurate flame retardant with an average particle size of 5 μm was equally replaced with silica, and then a reference specimen was prepared through the above process and used for the following experiments.

[0094] Detection method / Test method

[0095] Flame retardancy: The oxygen index was tested with reference to ASTM D2863;

[0096] Elongation at break and tensile strength: Refer to GB / T 528-1998;

[0097] Abrasion resistance: Refer to GB / T 1689-2014 Determination of abrasion resistance of vulcanized rubber (using an Akron abrasion tester). The specimen was strip-shaped, 480 mm long, 13 mm wide, and 3.0 mm thick. The load was 2 kg; the rotational speed of the grinding wheel shaft was 35 r / min; the grinding wheel abrasive could be alumina, with a particle size of 36, and the binder was clay; the number of running times was 3000 times, and the included angle between the rubber wheel shaft and the grinding wheel shaft was 23°. Calculate the mass wear rate.

[0098] High temperature resistance: The test samples obtained above were placed in an oven at 250°C for 7 days, and then the abrasion resistance was tested. The test method was the same as above, and the mass wear increment was calculated. The mass wear increment was equal to the mass wear rate after high temperature testing minus the mass wear rate before high temperature testing.

[0099] The above experiments are specifically shown in Table 1;

[0100] Experimental Results of Test Samples and Reference Specimens in Examples 1-11 and Comparative Examples 1-5

[0101]

[0102]

[0103] From the above experimental results, it can be seen that after the melamine cyanurate flame retardant prepared in this application is added, it can act as a filler and has better mechanical properties, flame retardant properties, wear resistance and heat resistance.

[0104] By comparing Example 1 with Comparative Examples 1-5, it can be seen that the oxygen index of Example 1 is above 41%, those of Comparative Examples 1-5 are below 38%, and the elongation at break and tensile strength of Comparative Examples 1-5 are lower than those of Example 1, while the mass wear rate and wear increment of Comparative Examples 1-5 are higher than those of Example 1. This shows that when using a crosslinking agent containing an isocyanate group, polysilazane, tris(2-hydroxyethyl)isocyanurate triacrylate, and alkyl acrylate phosphate to play a better synergistic role, and compounding them with the flowable white viscous substance (mainly melamine cyanurate) obtained by the process of this application, and then through the preparation process of this application, the obtained melamine cyanurate flame retardant has better flame retardant properties, wear resistance and compatibility with silicone rubber. When used in the production of silicone materials, it can further improve the comprehensive performance of silicone materials.

[0105] By comparing Example 4 with Examples 6-8 and combining Table 1, it can be seen that the oxygen index of Examples 6-8 is increased to above 45%, while the oxygen index of Example 4 is below 44%. The elongation at break and tensile strength of Example 4 are lower than those of Examples 6-8, and the mass wear rate and wear increment of Examples 6-8 are lower than those of Example 4. This shows that Examples 6-8 use a mixture of diisocyanate trimer and triallyl isocyanurate for compounding to play a synergistic role. When the obtained melamine cyanurate flame retardant is used in silicone materials, it can further improve wear resistance, mechanical properties, high temperature resistance and flame retardant properties.

[0106] By comparing Example 7 with Examples 10-11 and combining Table 1, it can be seen that the elongation at break, tensile strength and oxygen index of Examples 10-11 are higher than those of Example 7, and the mass wear rate and wear increment of Examples 10-11 are lower than those of Example 7. This shows that when using a polysilazane obtained by compounding perhydrogen inorganic polysilazane and organic polyborosilazane, and then mixing it with a mixture B obtained by combining a crosslinking agent containing an isocyanate group, tris(2-hydroxyethyl)isocyanurate triacrylate, and alkyl acrylate phosphate, and then compounding it with the flowable white viscous substance, the obtained melamine cyanurate flame retardant by the preparation process of this application has better wear resistance, mechanical properties, high temperature resistance and flame retardant properties.

[0107] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A preparation method of a melamine cyanurate flame retardant, characterized in that, Prepared by the following method: 1): By weight, weigh 5 - 8 parts of melamine and 10 - 20 parts of water and mix them evenly. After heating, add 3.5 - 6.8 parts of cyanuric acid, 0.3 - 0.8 parts of flame retardant filler, and 0.01 - 0.015 parts of alkali metal and mix them evenly. React until the viscosity is 8000 - 9000 mPa·s to obtain reactant A; By weight, weigh 0.01 - 0.3 parts of isocyanate group-containing crosslinking agent, 0.1 - 0.3 parts of polysilazane, 0.1 - 0.5 parts of tris(2-hydroxyethyl)isocyanurate triacrylate, 0.2 - 0.5 parts of alkyl acrylate phosphate, 0.001 - 0.003 parts of peroxide, and 10 - 20 parts of solvent and mix them evenly to obtain mixture B; 2): Filter reactant A to obtain a flowable white viscous substance, then add all of it to mixture B and mix evenly. React, dry, and crush to obtain the melamine cyanurate flame retardant.

2. The preparation method of a melamine cyanurate flame retardant according to claim 1, characterized in that: The flame retardant filler is composed of one or more of hydrotalcite, titanium dioxide, and antimony trioxide.

3. The preparation method of a melamine cyanurate flame retardant according to claim 2, wherein: The flame retardant filler is composed of hydrotalcite and antimony trioxide in a weight ratio of 1:(1 - 3).

4. The preparation method of a melamine cyanurate flame retardant according to claim 1, characterized in that: The isocyanate group-containing crosslinking agent is diisocyanate trimer and / or triallyl isocyanurate.

5. The preparation method of a melamine cyanurate flame retardant according to claim 2, characterized in that: The isocyanate group-containing crosslinking agent is composed of diisocyanate trimer and / or triallyl isocyanurate in a weight ratio of 1:(0.1 - 0.3).

6. The preparation method of a melamine cyanurate flame retardant according to claim 1, characterized in that: The polysilazane is perhydrogenated inorganic polysilazane and / or organic polyborosilazane.

7. The preparation method of a melamine cyanurate flame retardant according to claim 2, characterized in that: The polysilazane is composed of perhydrogenated inorganic polysilazane and organic polyborosilazane in a weight ratio of 1:(2 - 3).

8. The preparation method of a melamine cyanurate flame retardant according to claim 1, characterized in that: The heating temperature in step 1) is 90 - 95 °C; the reaction temperature in step 2) is 65 - 75 °C.

9. The preparation method of a melamine cyanurate flame retardant according to claim 1, characterized in that: The drying temperature in step 2) is 120 - 150 °C.

10. A melamine cyanurate flame retardant, characterized in that: Produced by the preparation method of a melamine cyanurate flame retardant according to any one of claims 1 - 9, and the particle size of the melamine cyanurate flame retardant is less than 100 microns.

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