Multi-piperidyl pyrimidine coupled brucite composite powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of natural mineral materials, and provides multi-piperidyl pyrimidine coupled brucite composite powder as well as a preparation method and application thereof. The preparation method comprises the following steps: dispersing multi-piperidinyl pyrimidine in an organic solvent to obtain a multi-piperidinyl pyrimidine solution, and dispersing 3-trimethylsilyl propiolaldehyde in an alcohol-water mixed solution to obtain a triple-bond silane solution; adding the triple-bond silane solution into the multi-piperidinyl pyrimidine solution for reaction to obtain multi-piperidinyl pyrimidine triple-bond silane; the preparation method comprises the following steps: dispersing multi-piperidyl pyrimidine triple-bond silane in an alcohol-water mixed solution to obtain a multi-piperidyl pyrimidine triple-bond silane solution; and spraying the multi-piperidyl pyrimidine triple-bond silane solution into the natural brucite powder. According to the invention, traditional triple-bond silane is fused with a natural product polypiperidinyl pyrimidine, and then is combined with natural brucite, so that composite powder fused with various natural products is obtained, and the composite powder has relatively good chemical reactivity, structural stability and multiple functions; and the preparation process is simple and environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of natural mineral materials, and particularly relates to a multi-piperidyl pyrimidine coupled brucite composite powder and a preparation method and application thereof. BACKGROUND

[0002] Natural brucite is a magnesium salt mineral with wide distribution and large reserves, and the main component is hydrated magnesium hydroxide. The superfine powder of the brucite treated by ball milling has a filling effect, and can realize the effects of reinforcement, whitening, smoke suppression and flame retardation, and is widely applied to the fields of coatings, fibers, rubber and plastic products and the like. Modifying and applying the natural brucite powder can not only effectively alleviate the problems of fossil energy consumption and high carbon emission, but also significantly improve the application value of natural minerals.

[0003] In the preparation process of traditional inorganic powder, a coupling agent is usually used for surface modification or modification of the inorganic powder. However, most of the coupling agents are modified by shielding the hydroxyl groups on the surface of the natural inorganic powder, and there are many defects in performance, which makes it difficult to improve the comprehensive performance of the inorganic powder. Moreover, the traditional coupling agent is a chemical product, which depends on a complicated preparation process and has high carbon emission, and it is difficult to meet the requirements of sustainable development at present.

[0004] Therefore, it is urgent to develop a new modification method of natural brucite, which can not only reduce the surface polarity of the natural brucite, but also effectively improve the properties of pyrolysis charring, internal and external synergistic flame retardation, smoke suppression and the like, and has a low oil absorption value. SUMMARY

[0005] The present application aims at providing a multi-piperidyl pyrimidine coupled brucite composite powder and a preparation method and application thereof to overcome the deficiencies of the prior art.

[0006] In order to achieve the above-mentioned application purpose, the present application provides the following technical scheme:

[0007] The present application provides a preparation method of a multi-piperidyl pyrimidine coupled brucite composite powder, which comprises the following steps:

[0008] 1) dispersing the multi-piperidyl pyrimidine in an organic solvent to obtain a multi-piperidyl pyrimidine solution;

[0009] dispersing 3-trimethylsilyl propargyl aldehyde in an alcohol-water mixture to obtain a triple bond silane solution;

[0010] 2) adding the triple bond silane solution to the multi-piperidyl pyrimidine solution to react, to obtain a multi-piperidyl pyrimidine triple bond silane;

[0011] 3) dispersing the multi-piperidyl pyrimidine triple bond silane in an alcohol-water mixture to obtain a multi-piperidyl pyrimidine triple bond silane solution;

[0012] 4) spray the solution of the polypiperidyl pyrimidine tri-silane into the natural brucite powder to obtain the polypiperidyl pyrimidine functionalized brucite composite powder.

[0013] Preferably, the polypiperidyl pyrimidine in step 1) is 6-(1-piperidyl)-2,4-pyrimidinediamine-3-oxide, and the structure of the polypiperidyl pyrimidine is

[0014] Preferably, the organic solvent in step 1) comprises an alcohol solvent and a non-alcohol solvent, and the volume ratio of the alcohol solvent to the non-alcohol solvent is 1-10:1.

[0015] The alcohol in the alcohol-water mixture in step 1) comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol, and 1,2-propanediol, and the volume ratio of the alcohol to water in the alcohol-water mixture is 1-3:1.

[0016] The concentration of the polypiperidyl pyrimidine solution is 1-5 mol / L.

[0017] The concentration of the tri-silane solution is 1-3 mol / L.

[0018] Preferably, the alcohol solvent comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol, and 1,2-propanediol.

[0019] The non-alcohol solvent comprises one or more of tetrahydrofuran, N,N-dimethylformamide, acetonitrile, ethyl acetate, and dimethyl sulfoxide.

[0020] Preferably, the rate of the addition in step 2) is 1-20 mL / min, and the polypiperidyl pyrimidine solution is stirred at a speed of 300-1000 rpm during the addition.

[0021] The molar ratio of the polypiperidyl pyrimidine in the polypiperidyl pyrimidine solution to 3-trimethylsilyl propargyl aldehyde in the tri-silane solution is 1-5:1.

[0022] Preferably, the temperature of the reaction in step 2) is 60-120°C, and the reaction time is 3-24 h.

[0023] Preferably, the alcohol in the alcohol-water mixture in step 3) comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol, and 1,2-propanediol, and the volume ratio of the alcohol to water in the alcohol-water mixture is 1-5:1.

[0024] The concentration of the polypiperidyl pyrimidine tri-silane solution is 1-3 mol / L.

[0025] Preferably, the spraying rate of step 4) is 10-100 mL / min, and the natural brucite powder is stirred during the spraying process at a stirring speed of 300-1000 rpm.

[0026] The molar mass ratio of the polypyridylpyrimidine triketone silane in the polypyridylpyrimidine triketone silane solution to the natural brucite powder is 1-3 mol:10 kg.

[0027] The median particle size D50 of the natural brucite powder is 0.9-4.5 μm. 50 The median particle size D50 of the polypyridylpyrimidine triketone silane solution is 1.0-4.6 μm.

[0028] The application further provides a polypyridylpyrimidine triketone silane complex brucite composite powder prepared by the preparation method. 50 The median particle size D50 of the polypyridylpyrimidine triketone silane solution is 1.0-4.6 μm.

[0029] The application further provides an application of the polypyridylpyrimidine triketone silane complex brucite composite powder in an elastomer.

[0030] The application has the following advantages:

[0031] 1) The application fuses a traditional triketone silane with a natural product polypyridylpyrimidine, and then combines the natural product with natural brucite, to obtain a composite powder fusing multiple natural products, the organic functional layer molecules on the surface of the composite powder have low polarity, can effectively shield the hydroxyl groups on the surface of the natural brucite, significantly reduce the surface polarity of the natural brucite, and make the composite powder have good chemical reactivity, structural stability and multiple functionalities, improve the compatibility and flowability of the composite powder in a low-polarity elastomer; meanwhile, the organic-inorganic synergistic components are introduced into the elastomer, to realize the common introduction of multiple functional components, make the organic-inorganic components play a synergistic effect at the same position, and avoid the physical separation phenomenon.

[0032] 2) The polyazepinyl pyrimidine complexed brucite powder (MND-TMP-UNB) of the present application has a core-shell structure, the outer shell layer is a triple bond silane modified by a natural product polyazepinyl pyrimidine, and the inner core layer is natural brucite powder. The external triple bond, nitrogen heterocycle, Schiff base, amino and other functional groups can make the composite powder rapidly char and promote the rapid generation of N heteroaromatic ring to form a better physical barrier layer; the internal natural brucite has the functions of smoke suppression, dehydration and heat absorption, and can produce a large amount of magnesium oxide ceramic precursor product during the combustion process, and the carbonates produced outside can be attached to the magnesium oxide ceramic precursor product to form a physical barrier layer that can resist heat flow, direct current and airflow impact; the core-shell structure cooperatively plays the roles of flame retardation, smoke suppression, carbonation, barrier and sealing of molecular chain fragments, thereby significantly improving the flame retardation, smoke suppression, thermal stability and carbonation performance of the elastomer; at the same time, the introduction of the external polyazepinyl pyrimidine triple bond silane can effectively improve the dispersibility of the natural brucite in the low polarity elastomer and enhance the mechanical properties of the elastomer.

[0033] 3) The polyazepinyl pyrimidine complexed brucite powder can be obtained by a two-step method, the preparation process is simple, green and environmentally friendly, does not depend on precise equipment, and is suitable for large-scale production; the polyazepinyl pyrimidine complexed brucite powder prepared by the present application is a white or off-white powder, is easy to color, can effectively expand the application range of natural brucite, and improve the added value. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The particle size distribution diagram of the polyazepinyl pyrimidine complexed brucite powder prepared for Example 1;

[0035] Figure 2 The scanning electron microscope diagram of the polyazepinyl pyrimidine complexed brucite powder prepared for Example 1. DETAILED DESCRIPTION

[0036] The present application provides a preparation method of a polyazepinyl pyrimidine complexed brucite powder, comprising the following steps:

[0037] 1) Disperse the polyazepinyl pyrimidine in an organic solvent to obtain a polyazepinyl pyrimidine solution;

[0038] Disperse 3-trimethylsilyl propargyl aldehyde in an alcohol-water mixture to obtain a triple bond silane solution;

[0039] 2) Add the triple bond silane solution to the polyazepinyl pyrimidine solution to react, to obtain a polyazepinyl pyrimidine triple bond silane;

[0040] 3) Disperse the polyazepinyl pyrimidine triple bond silane in an alcohol-water mixture to obtain a polyazepinyl pyrimidine triple bond silane solution;

[0041] 4) spray the solution of the polypiperidyl pyrimidine tri-silane to the natural brucite powder, and obtain the polypiperidyl pyrimidine complexed brucite powder.

[0042] In the present application, the polypiperidyl pyrimidine in step 1) is preferably 6-(1-piperidyl)-2,4-pyrimidine diamine-3-oxide, and the structural formula of the polypiperidyl pyrimidine is

[0043] In the present application, the organic solvent in step 1) preferably comprises an alcohol solvent and a non-alcohol solvent, and the volume ratio of the alcohol solvent and the non-alcohol solvent is preferably 1-10:1, further preferably 3-8:1, and more preferably 5:1.

[0044] The alcohol in the alcohol-water mixture in step 1) preferably comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol and 1,2-propanediol, and the volume ratio of alcohol and water in the alcohol-water mixture is preferably 1-3:1, further preferably 1.5-2.5:1, and more preferably 2:1.

[0045] The concentration of the polypiperidyl pyrimidine solution is preferably 1-5 mol / L, further preferably 2-4 mol / L, and more preferably 3 mol / L.

[0046] The concentration of the tri-silane solution is preferably 1-3 mol / L, further preferably 1.5-2.5 mol / L, and more preferably 2 mol / L.

[0047] In the present application, the alcohol solvent preferably comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol and 1,2-propanediol.

[0048] The non-alcohol solvent preferably comprises one or more of tetrahydrofuran, N,N-dimethylformamide, acetonitrile, ethyl acetate and dimethyl sulfoxide.

[0049] In the present application, the polypiperidyl pyrimidine in step 1) is preferably 6-(1-piperidyl)-2,4-pyrimidine diamine-3-oxide, and the structural formula of the polypiperidyl pyrimidine is

[0050] In the present application, the 3-trimethylsilylpropynal in step 1) is dispersed in the alcohol-water mixture solution preferably with stirring, the stirring speed is preferably 500-1200 rpm, further preferably 700-1000 rpm, more preferably 800 rpm; the stirring time is preferably 1-3 h, further preferably 2 h; the temperature of dispersing the 3-trimethylsilylpropynal in the alcohol-water mixture solution is preferably 20-50℃, further preferably 30-40℃, more preferably 35℃.

[0051] In the present application, the addition rate in step 2) is preferably 1-20 mL / min, further preferably 5-15 mL / min, more preferably 10 mL / min; the polypiperidylpyrimidine solution is preferably stirred during the addition, the stirring speed is preferably 300-1000 rpm, further preferably 500-800 rpm, more preferably 600 rpm.

[0052] The molar ratio of polypiperidylpyrimidine in the polypiperidylpyrimidine solution to 3-trimethylsilylpropynal in the triple bond silane solution is preferably 1-5:1, further preferably 2-4:1, more preferably 3:1.

[0053] In the present application, after the addition in step 2) is completed, the stirring is preferably continued and the temperature is raised to the reaction temperature, the stirring speed during the continued stirring is preferably 1200-2500 rpm, further preferably 1500-2000 rpm, more preferably 1800 rpm; the temperature raising rate is preferably 10-60℃ / min, further preferably 20-50℃ / min, more preferably 30-40℃ / min.

[0054] In the present application, the reaction temperature in step 2) is preferably 60-120℃, further preferably 70-110℃, more preferably 90℃; the reaction time is preferably 3-24 h, further preferably 8-20 h, more preferably 14-18 h.

[0055] In the present application, the reaction route in step 2) is preferably

[0056]

[0057] In the present application, after the reaction in step 2) is completed, it is preferably cooled to room temperature, and then sequentially spin-dried, precipitated, filtered, and dried to obtain the poly-piperidyl pyrimidine triple bond silane; the vacuum degree of the spin-drying is preferably -0.09 to -0.07 MPa, and further preferably -0.08 MPa; the rotation speed of the spin-drying is preferably 30 to 300 rpm, and further preferably 100 to 200 rpm, and more preferably 150 rpm; the spin-drying time is preferably 10 to 45 min, and further preferably 12 to 30 min; the precipitation is preferably that the product after spin-drying is dispersed in dichloromethane to obtain a suspension, and then precipitated by standing; the mass-volume ratio of the product after spin-drying to dichloromethane is preferably 1 to 10 mg: 1 mL, and further preferably 5 mg: 1 mL; the standing temperature is preferably 1 to 10°C, and further preferably 5°C; the standing time is preferably 3 to 36 h, and further preferably 10 to 30 h, and more preferably 18 h; the filtration is preferably carried out in ethyl acetate, the filter paper used is preferably medium-speed filter paper, the number of layers of the filter paper is preferably 1 to 3 layers, and further preferably 2 layers; the flow rate of the filtration is preferably 0.1 to 1.0 mL / s, and further preferably 0.5 mL / s; the number of times of the filtration is preferably 1 to 3 times, and further preferably 2 times; and the drying is preferably freeze-drying, the freeze-drying temperature is preferably -30 to -5°C, and further preferably -20 to -10°C, and more preferably -15°C; and the freeze-drying time is preferably 8 to 36 h, and further preferably 18 to 28 h, and more preferably 24 h.

[0058] In the present application, the alcohol in the alcohol-water mixture in step 3) preferably comprises one or more of methanol, anhydrous ethanol, propanol, ethylene glycol, and 1,2-propanediol, and the volume ratio of alcohol to water in the alcohol-water mixture is preferably 1 to 5: 1, and further preferably 2 to 4: 1, and more preferably 3: 1.

[0059] The concentration of the poly-piperidyl pyrimidine triple bond silane solution is preferably 1 to 3 mol / L, and further preferably 1.5 to 2.5 mol / L, and more preferably 2 mol / L.

[0060] In the present application, the dispersion in step 3) is preferably carried out by stirring, and the stirring speed is preferably 100 to 600 rpm, and further preferably 300 rpm; and the stirring time is preferably 20 to 50 min, and further preferably 30 to 40 min.

[0061] In the present application, the spraying rate in step 4) is preferably 10 to 100 mL / min, and further preferably 30 to 80 mL / min, and more preferably 50 mL / min; and the natural water-magnesium stone powder is preferably stirred during the spraying, and the stirring speed is preferably 300 to 1000 rpm, and further preferably 500 to 800 rpm, and more preferably 600 rpm.

[0062] The molar mass ratio of the polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder is preferably 1-3 mol: 10 kg, further preferably 1.5-2.5 mol: 10 kg, and more preferably 2 mol: 10 kg.

[0063] The median particle size D50 of the natural brucite powder is preferably 0.9-4.5 μm, further preferably 1.5-4 μm, and more preferably 2-3 μm. 50 The median particle size D50 of the natural brucite powder is preferably 0.9-4.5 μm, further preferably 1.5-4 μm, and more preferably 2-3 μm.

[0064] In the present application, when the molar mass ratio of the polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder is less than 1 mol: 10 kg, the amount of the polypyridyl pyrimidine triketone silane added is too low, and it is difficult to effectively cover and shield the natural brucite powder, the functionalization enhancement effect is limited, and the comprehensive performance of the composite powder is not good. When the molar mass ratio of the polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder is more than 3 mol: 10 kg, the amount of the polypyridyl pyrimidine triketone silane added is too large, and most of the polypyridyl pyrimidine triketone silane exists on the surface of the natural brucite powder in a physical adsorption manner, and uneven dispersion occurs. In the subsequent modification or processing process, not only is it easy to be mechanically stripped, but also the content of the polypyridyl pyrimidine triketone silane in the local area of the surface is too large, and even multiple natural brucite powders are wrapped, which is easy to induce fracture when subjected to external impact. At the same time, the dispersibility in the elastomer is also reduced.

[0065] In the present application, the synthesis route of the polypyridyl pyrimidine coupled brucite composite powder in step 4) is preferably In the present application, the synthesis route of the polypyridyl pyrimidine coupled brucite composite powder in step 4) is preferably

[0066]

[0067] The natural brucite powder is UNB.

[0068] The polypyridyl pyrimidine coupled brucite composite powder has a typical organic functional layer of polypyridyl pyrimidine coupled triketone silane (MND-TMP), which contains Si elements, triple bonds, N heterocycles, amino groups, and Schiff bases, etc. The core is the natural brucite powder (UNB).

[0069] In the present application, the natural brucite is preferably heated during the spraying process of step 4), and the heating rate is preferably 1-5℃ / min, further preferably 2-3℃ / min; after the spraying is completed, the stirring is preferably continued and the heating is also continued, the stirring speed is preferably 300-1000rpm, further preferably 500-800rpm, more preferably 600rpm; the time for the continued stirring is preferably 0.1-1.2h, further preferably 0.5-0.8h; the heating rate for the continued heating is preferably 0.5-2.5℃ / min, further preferably 1-2℃ / min, more preferably 1.5℃ / min;

[0070] After the continued stirring is completed, the heating is preferably stopped and the cooling to room temperature is performed, and then the dust removal and drying are sequentially performed, thereby obtaining the poly-piperidyl pyrimidine complexed brucite powder; the power for the dust removal is preferably 100-400W, further preferably 200-300W; the stirring speed for the dust removal is preferably 800-3200rpm, further preferably 1600-2500rpm; the air volume for the dust removal is preferably 50-200m 3 / h, further preferably 100-150m 3 / h; the number of times for the dust removal is preferably 1-3, further preferably 2; the time for each dust removal is preferably 2-10s, further preferably 3-8s; the drying is preferably flash drying, the temperature for the flash drying is preferably 180-230℃, further preferably 200℃; the time for the flash drying is preferably 0.2-1min, further preferably 0.5min; the power for the flash drying is preferably 800-1600W, further preferably 1000-1200W.

[0071] The present application also provides the poly-piperidyl pyrimidine complexed brucite powder prepared by the preparation method, and the median particle size D 50 of the poly-piperidyl pyrimidine complexed brucite powder is 1.0-4.6μm.

[0072] In the present application, the appearance of the poly-piperidyl pyrimidine complexed brucite powder is preferably white or off-white powder.

[0073] The present application also provides the application of the poly-piperidyl pyrimidine complexed brucite powder in elastomers.

[0074] The technical solutions provided by the present application will be described in detail below in combination with examples, but they should not be understood as limitations to the protection scope of the present application.

[0075] The poly-piperidyl pyrimidine used in the examples and comparative examples of the present application is 6-(1-piperidyl)-2,4-pyrimidine diamine-3-oxide, and the structural formula is

[0076] The natural brucite powder used in the examples and comparative examples of the present application is GY high-magnesium series natural brucite powder produced by Jiangxi Guangyuan Chemical Industry Co., Ltd., and the content of magnesium hydroxide component is more than 90wt%.

[0077] Example 1

[0078] ①At 25℃, 2mol of polypiperidyl pyrimidine was added to an organic solvent of tetrahydrofuran and methanol in a volume ratio of 1:5, and stirred at a speed of 300rpm for 2.5h to obtain a polypiperidyl pyrimidine solution with a concentration of 2mol / L. At 30℃, 1mol of 3-trimethylsilyl propargyl aldehyde was added to an alcohol-water mixture of anhydrous ethanol and purified water in a volume ratio of 3:1, and stirred at a speed of 800rpm for 2h to obtain a triple bond silane solution with a concentration of 1mol / L.

[0079] ②The triple bond silane solution was added to the polypiperidyl pyrimidine solution at a speed of 20mL / min, and the polypiperidyl pyrimidine solution was stirred at a speed of 1000rpm during the addition. The molar ratio of polypiperidyl pyrimidine in the polypiperidyl pyrimidine solution to 3-trimethylsilyl propargyl aldehyde in the triple bond silane solution was 1:1. After the addition was completed, the mixture was continuously stirred at a speed of 1800rpm, and the mixture was heated to 90℃ at a rate of 30℃ / min, and reacted at 90℃ for 18h to obtain a reaction liquid. After the reaction was completed, the reaction liquid was cooled to room temperature, and the solvent was removed by rotary evaporation at a speed of 150rpm under a pressure of-0.08MPa for 25min. The rotary-evaporated product was dispersed in dichloromethane to obtain a suspension, and the mass-volume ratio of the rotary-evaporated product to dichloromethane was 5mg:1mL. The suspension was statically placed at 5℃ for 18h, and crystals were precipitated and separated out. The crystals precipitated and separated out were suction-filtered twice in ethyl acetate at a flow rate of 0.5mL / s using 2 layers of medium-speed filter paper (qualitative filter paper, Titan technology), and then freeze-dried at-15℃ for 18h to obtain polypiperidyl pyrimidine triple bond silane.

[0080] ③At 25℃, 3mol of polypiperidyl pyrimidine triple bond silane was added to an alcohol-water mixture of anhydrous ethanol and purified water in a volume ratio of 1:1, and stirred at a speed of 300rpm for 30min to obtain a polypiperidyl pyrimidine triple bond silane solution with a concentration of 3mol / L.

[0081] ④At 45℃, 10kg of medium particle size D 50The natural brucite powder with a particle size of 2 pm (UNB) was placed in a high-speed blender stirred at a speed of 600 rpm, and the polypyridyl pyrimidine tri-silane solution was sprayed into the natural brucite powder at a speed of 10 mL / min (the molar mass ratio of polypyridyl pyrimidine tri-silane in the polypyridyl pyrimidine tri-silane solution to the natural brucite powder was 1 mol:10 kg), and the natural brucite powder was heated at a rate of 3 °C / min until the spraying was completed, and the stirring was continuously performed at a speed of 600 rpm during the spraying. After the spraying was completed, the stirring was continued at a speed of 600 rpm for 0.8 h, while the temperature was increased at a rate of 1.5 °C / min to 80 °C. After the continuous stirring was completed, the heating was stopped and the temperature was cooled to room temperature. The mixed powder was placed in a cyclone separator, and the dust was removed twice at a speed of 1600 rpm for 5 s each time under the conditions of a power of 200 W and an air volume of 100 m 3 / h. After the dust removal was completed, the obtained powder was flash dried at 1200 W and 200 °C for 0.5 min, to obtain the polypyridyl pyrimidine modified brucite composite powder (MND-TMP-UNB).

[0082] The median particle size D 50 was 2.1 pm.

[0083] Figure 1 The particle size distribution graph of the polypyridyl pyrimidine modified brucite composite powder prepared in Example 1. It can be seen that the particle size distribution of the polypyridyl pyrimidine modified brucite composite powder (MND-TMP-UNB) was relatively uniform, showing a good unimodal shape, and was concentrated near 2.1 pm. Figure 1

[0084] Figure 2 The scanning electron microscope graph of the polypyridyl pyrimidine modified brucite composite powder prepared in Example 1. It can be seen that there was a relatively obvious multi-point coating on the surface of the polypyridyl pyrimidine modified brucite composite powder, and there was a significant hybrid modification effect. Figure 2

[0085] Example 2

[0086] ①At 25 °C, 5 mol of polypyridyl pyrimidine was added to an organic solvent of N,N-dimethylformamide and ethylene glycol in a volume ratio of 1:1, and stirred at a speed of 800 rpm for 0.5 h to obtain a polypyridyl pyrimidine solution with a concentration of 5 mol / L. At 20 °C, 2 mol of 3-trimethylsilyl propargyl aldehyde was added to an alcohol-water mixture of methanol and purified water in a volume ratio of 2:1, and stirred at a speed of 1200 rpm for 3 h to obtain a tri-silane solution with a concentration of 2 mol / L.

[0087] ​​(2) The tris-silane solution was added to the poly-piperidyl pyrimidine solution at a rate of 1 mL / min, and the poly-piperidyl pyrimidine solution was stirred at a speed of 600 rpm during the addition. The molar ratio of poly-piperidyl pyrimidine in the poly-piperidyl pyrimidine solution to 3-trimethylsilylpropynal in the tris-silane solution was 3:1. After the addition was completed, the mixture was continuously stirred at a speed of 1200 rpm, and the mixture was heated to 60°C at a rate of 30°C / min and reacted at 60°C for 24 h to obtain a reaction solution. After the reaction was completed, the reaction solution was cooled to room temperature, and the solvent was removed by rotary evaporation at a speed of 30 rpm under a pressure of -0.07 MPa for 45 min. The rotary-evaporated product was dispersed in dichloromethane to obtain a suspension, and the mass-volume ratio of the rotary-evaporated product to dichloromethane was 1 mg:1 mL. The suspension was allowed to stand at 1°C for 3 h, and crystals were precipitated. The precipitated crystals were suction-filtered three times in ethyl acetate at a flow rate of 1.0 mL / s using one layer of medium-speed filter paper (qualitative filter paper, Titan technology), and then freeze-dried at -30°C for 8 h to obtain poly-piperidyl pyrimidine tris-silane.

[0088] (3) At 25°C, 2 mol of poly-piperidyl pyrimidine tris-silane was added to an alcohol-water mixture of anhydrous ethanol and purified water in a volume ratio of 5:1, and stirred at a speed of 100 rpm for 50 min to obtain a poly-piperidyl pyrimidine tris-silane solution with a concentration of 2 mol / L.

[0089] (4) At 30°C, 10 kg of natural brucite powder (UNB) with a median particle size D 50 was placed in a high-speed blender stirred at a speed of 300 rpm, and the poly-piperidyl pyrimidine tris-silane solution was sprayed at a rate of 50 mL / min into the natural brucite powder (the molar mass ratio of poly-piperidyl pyrimidine tris-silane in the poly-piperidyl pyrimidine tris-silane solution to the natural brucite powder was 2 mol:10 kg), and the natural brucite powder was heated at a rate of 1°C / min until the spraying was completed. The stirring was continuously performed at a speed of 300 rpm during the spraying. After the spraying was completed, the stirring was continuously performed at a speed of 300 rpm for 1.2 h while heating at a rate of 0.5°C / min to 60°C. After the continuous stirring was completed, the heating was stopped and the temperature was cooled to room temperature. The mixed powder was placed in a cyclone separator, and the dust was removed three times at a power of 100 W and an air volume of 50 m 3 / h at a speed of 3200 rpm, and the time for each dust removal was 10 s. After the dust removal was completed, the obtained powder was flash-dried at 800 W and 180°C for 1 min to obtain a poly-piperidyl pyrimidine complexed brucite composite powder.

[0090] The median particle size D 50 of the poly-piperidyl pyrimidine complexed brucite composite powder prepared in this example was 1.0 μm.

[0091] Example 3

[0092] ① At 25℃, 1 mol of polypiperidylpyrimidine was added to an organic solvent of acetonitrile and 1,2-propanediol in a volume ratio of 1:10, and stirred at a speed of 100 rpm for 3.5 h to obtain a polypiperidylpyrimidine solution with a concentration of 1 mol / L. At 50℃, 3 mol of 3-trimethylsilylpropynal was added to an alcohol-water mixture of ethylene glycol and purified water in a volume ratio of 2:1, and stirred at a speed of 500 rpm for 1 h to obtain a triple bond silane solution with a concentration of 3 mol / L.

[0093] ② The triple bond silane solution was added to the polypiperidylpyrimidine solution at a speed of 10 mL / min, and the polypiperidylpyrimidine solution was stirred at a speed of 300 rpm during the addition. The molar ratio of polypiperidylpyrimidine in the polypiperidylpyrimidine solution to 3-trimethylsilylpropynal in the triple bond silane solution was 5:1. After the addition was completed, the mixture was continuously stirred at a speed of 2500 rpm, and the mixture was heated to 120℃ at a rate of 60℃ / min, and reacted at 120℃ for 3 h to obtain a reaction solution. After the reaction was completed, the reaction solution was cooled to room temperature, and the solvent was removed by rotary evaporation at a speed of 300 rpm under a pressure of -0.09 MPa for 15 min. The rotary-evaporated product was dispersed in dichloromethane to obtain a suspension, and the mass volume ratio of the rotary-evaporated product to dichloromethane was 10 mg:1 mL. The suspension was allowed to stand at 10℃ for 36 h, and crystals were precipitated. The precipitated crystals were filtered once in ethyl acetate at a flow rate of 0.1 mL / s using 3 layers of medium-speed filter paper (qualitative filter paper, Titan technology), and then freeze-dried at -5℃ for 36 h to obtain polypiperidylpyrimidine triple bond silane.

[0094] ③ At 25℃, 1 mol of polypiperidylpyrimidine triple bond silane was added to an alcohol-water mixture of anhydrous ethanol and purified water in a volume ratio of 3:1, and stirred at a speed of 600 rpm for 20 min to obtain a polypiperidylpyrimidine triple bond silane solution with a concentration of 1 mol / L.

[0095] ④ At 55℃, 10 kg of polypiperidylpyrimidine triple bond silane was added to an alcohol-water mixture of anhydrous ethanol and purified water in a volume ratio of 3:1, and stirred at a speed of 600 rpm for 20 min to obtain a polypiperidylpyrimidine triple bond silane solution with a concentration of 10 kg / L. 50The natural brucite powder with a particle size of 4.5 μm (UNB) was placed in a high-speed blender stirred at a speed of 1000 rpm, the polypyridyl pyrimidine triketone silane solution was sprayed into the natural brucite powder at a speed of 50 mL / min (the molar mass ratio of polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder was 3 mol:10 kg), and the natural brucite powder was heated at a rate of 2 ℃ / min until the spraying was completed. The stirring was continued at a speed of 1000 rpm during the spraying. After the spraying was completed, the stirring was continued at a speed of 1000 rpm for 0.1 h while heating at a rate of 2.5 ℃ / min to 100 ℃. The stirring was stopped after the heating was continued, and the temperature was cooled to room temperature. The mixed powder was placed in a cyclone separator, and the dust was removed at a speed of 800 rpm for 2 s under the conditions of a power of 400 W and an air volume of 200 m 3 / h. After the dust removal was completed, the obtained powder was flash dried at 1600 W and 230 ℃ for 0.2 min, and a polypyridyl pyrimidine triketone silane modified natural brucite composite powder was obtained.

[0096] The median particle size D 50 was 4.6 μm.

[0097] Comparative Example 1

[0098] The molar mass ratio of polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder in Example 1 was modified to 0.5 mol:10 kg, and the other conditions were the same as in Example 1.

[0099] Comparative Example 2

[0100] The molar mass ratio of polypyridyl pyrimidine triketone silane in the polypyridyl pyrimidine triketone silane solution to the natural brucite powder in Example 1 was modified to 5 mol:10 kg, and the other conditions were the same as in Example 1.

[0101] The polypyridyl pyrimidine triketone silane modified natural brucite composite powders prepared in Examples 1-3 and Comparative Examples 1-2 and the natural brucite powder (GY-6000 series powder produced by Jiangxi Guangyuan Chemical Industry Co., Ltd.) were tested for activation rate, oil absorption value, and contact angle. The activation rate was tested by a weighing method, the oil absorption value was tested according to DB / T 5211.15-2014, and the contact angle was tested by an OCA20 optical contact angle measuring instrument. The test results are shown in Table 1.

[0102] Table 1 Test results of powder performance

[0103] Activation rate / % Oil absorption value (mL / 100g) Contact angle (°) Example 1 90.5 24 102.2 Example 2 88.4 25 97.5 Example 3 89.2 25 99.8 Comparative Example 1 56.3 34 38.3 Comparative Example 2 61.5 32 67.5 Natural brucite powder 38.2 38 16.2

[0104] As can be seen from Table 1, the activation rate and contact angle of the natural brucite powder modified by the polypyridyl pyrimidine triple bond silane are significantly improved, and the oil absorption value is decreased. The activation rate is increased from 38.2% to 90.5%, and the contact angle is increased from 16.2° to 102.2°. It is shown that the polypyridyl pyrimidine triple bond silane can reduce the surface energy of the natural brucite powder, effectively reduce the surface polarity of the natural brucite, improve the hydrophobicity, and then reduce the adsorption of the processing aid, so that the processing cost can be greatly reduced. In comparison, the improvement of the activation rate and the contact angle of the composite powder prepared in Comparative Examples 1-2 is not obvious due to the too low or too high addition amount of the polypyridyl pyrimidine triple bond silane. It is shown that due to the inappropriate addition amount of the polypyridyl pyrimidine triple bond silane, it is difficult to form an effective shielding on the surface of the natural brucite powder, and there is a large molar mass difference between the external functional layer and the internal natural brucite powder. When the addition amount of the polypyridyl pyrimidine triple bond silane is too low, it is difficult to effectively cover the natural brucite powder, and when the addition amount is too high, the polypyridyl pyrimidine triple bond silane may be physically adsorbed on the surface of the natural brucite powder, and wrap multiple natural brucite powders at the same time, which affects the processing performance. Since the modification is not effective, the activation rate, oil absorption value and contact angle of the composite powder obtained in Comparative Examples 1-2 are poorer than those of Examples 1-3. The natural brucite composite powder prepared in the application is modified by using a suitable addition amount of the polypyridyl pyrimidine triple bond silane, so that the activation rate, oil absorption value and contact angle of the composite powder are significantly changed, which is beneficial to the improvement of the subsequent processing performance of the composite powder.

[0105] Application Example 1

[0106] The polypyridyl pyrimidine complexed brucite composite powder prepared in Example 1 is added to ethylene-vinyl acetate copolymer (EVA). In terms of mass fraction, the polypyridyl pyrimidine complexed brucite composite powder prepared in Example 1 accounts for 12 parts, EVA accounts for 92 parts, antioxidant (1010) accounts for 1 part, compatible agent (MC226) accounts for 2 parts, silicone master batch (MB50-001) accounts for 2 parts, and oleic acid (OA) accounts for 1 part.

[0107] The preparation method is as follows: the oleic acid and EVA are mixed to obtain oil-impregnated EVA. The oil-impregnated EVA, compatible agent, silicone master batch, antioxidant and polypyridyl pyrimidine complexed brucite composite powder are placed in a high-speed mixer and mixed at a speed of 600 r / min for 2 min, then mixed at 150°C for 10 min, and then placed on a flat vulcanizing machine and hot-pressed at 150°C and 15 MPa for 10 min to obtain the EVA composite material.

[0108] Application Example 2

[0109] The polypyridyl pyrimidine complexed brucite composite powder in Application Example 1 is replaced with the polypyridyl pyrimidine complexed brucite composite powder prepared in Example 2, and the other conditions are the same as those in Application Example 1.

[0110] Application Example 3

[0111] The polypyridylpyrimidine-modified brucite composite powder in Application Example 1 was replaced with the polypyridylpyrimidine-modified brucite composite powder prepared in Example 3, and the rest was the same as in Application Example 1.

[0112] Application Comparative Example 1

[0113] The polypyridylpyrimidine-modified brucite composite powder in Application Example 1 was replaced with the polypyridylpyrimidine-modified brucite composite powder prepared in Application Comparative Example 1, and the rest was the same as in Application Example 1.

[0114] Application Comparative Example 2

[0115] The polypyridylpyrimidine-modified brucite composite powder in Application Example 1 was replaced with the polypyridylpyrimidine-modified brucite composite powder prepared in Application Comparative Example 2, and the rest was the same as in Application Example 1.

[0116] Application Comparative Example 3

[0117] The polypyridylpyrimidine-modified brucite composite powder in Application Example 1 was replaced with natural brucite powder (natural brucite powder GY-6000 series powder produced by Jiangxi Guangyuan Chemical Industry Co., Ltd.), and the rest was the same as in Application Example 1.

[0118] The composite materials in Application Examples 1-3 and Application Comparative Examples 1-3 were tested for performance, the balance torque during melt blending was determined using a SU-70 internal mixer, the total smoke release was tested according to ISO 5659-2-2017 (the heating power was 25 kW / m 2 ), the tensile strength was tested according to GB / T 1040.1-2018, the limiting oxygen index (LOI) was tested according to GB / T 8924-2005, and the combustion grade (VW-1) was tested according to UL1581:2020. The test results are shown in Table 2.

[0119] Table 2 Performance test results of EVA composite materials

[0120]

[0121] As can be seen from Table 2, the balance torque of Application Examples 1-3 and Application Comparative Examples 1-2 is lower than that of Application Comparative Example 3, indicating that modifying natural brucite powder with polypyridylpyrimidine triple bond silane can improve the dispersibility of natural brucite powder in the EVA matrix, significantly reduce the viscosity and internal friction of the EVA matrix, and increase the flowability. However, the balance torque improvement of Application Comparative Examples 1-2 is limited due to the inappropriate amount of polypyridylpyrimidine triple bond silane added, and the flowability improvement effect is not significant. In terms of total smoke release, Application Comparative Example 3 releases a large amount of smoke, reaching 15.4 kW / m 2, is due to the difficulty in forming an effective physical barrier layer, which cannot block the volatilization of molecular chain fragments in the combustion process, resulting in limited smoke suppression effect; when the natural brucite powder is modified by the polypyridyl pyrimidine triple bond silane, the total smoke release amount of application examples 1 to 3 and application comparative examples 1 to 2 decreases, because the external polypyridyl pyrimidine triple bond silane and the internal natural brucite powder have a synergistic effect, which can quickly form carbon during the combustion process, and the internal natural brucite powder pyrolysis product can well support the carbon layer, forming a stable, continuous and dense physical barrier layer, effectively blocking the release of smoke. In comparison, the total smoke release amount of application examples 1 to 3 is lower. In terms of tensile strength, application examples 1 to 3 and application comparative examples 1 to 2 add the composite powder modified by the polypyridyl pyrimidine triple bond silane, which can effectively disperse the composite powder in the EVA matrix, and can enhance the tensile properties of the molecular chain under external stress, so as not to become a stress concentration point. However, application comparative examples 1 to 2 have limited improvement in tensile strength due to poor modification effect. In terms of oxygen index, it is increased from 19.2% of application comparative example 3 to 28.2%, indicating that the synergistic effect of the external polypyridyl pyrimidine triple bond silane and the internal natural brucite powder can play a flame-retardant effect at multiple points, and when the modification effect is poor, the oxygen index is not obviously improved. The composite materials of application examples 1 to 3 can pass the VW-1 test, while application examples 1 to 2 have poor modification effect, which affects the performance of the composite material.

[0122] The natural brucite powder is modified by the polypyridyl pyrimidine triple bond silane in a suitable proportion, which can effectively improve the synergistic flame-retardant effect of the external functional layer and the internal natural brucite powder, and effectively improve the dispersibility and reinforcing effect of the composite powder in the EVA matrix, which significantly improves the processing performance, smoke suppression performance and mechanical properties of the EVA matrix.

[0123] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing a polypiperidinylpyrimidine-coupled brucite composite powder, characterized in that, It includes the following steps: 1) Disperse polypiperidinylpyrimidine in an organic solvent to obtain a polypiperidinylpyrimidine solution; 3-Trimethylsilylpropynaldehyde was dispersed in an alcohol-water mixture to obtain a triple-bonded silane solution; 2) Add the triple-bonded silane solution to the piperidinyl pyrimidine solution and react to obtain the piperidinyl pyrimidine triple-bonded silane; 3) Disperse the polypiperidinylpyrimidine triple bond silane in an alcohol-water mixture to obtain a polypiperidinylpyrimidine triple bond silane solution; 4) Spray the polypiperidinylpyrimidine triple bond silane solution into natural brucite powder to obtain polypiperidinylpyrimidine coupled brucite composite powder.

2. The preparation method according to claim 1, characterized in that, Step 1) The polypiperidinylpyrimidine is 6-(1-piperidinyl)-2,4-pyrimidinediamine-3-oxide, and the structural formula of the polypiperidinylpyrimidine is:

3. The preparation method according to claim 1 or 2, characterized in that, Step 1) The organic solvent includes alcohol solvents and non-alcohol solvents, and the volume ratio of alcohol solvents to non-alcohol solvents is 1 to 10:1; Step 1) The alcohol in the alcohol-water mixture includes one or more of methanol, anhydrous ethanol, propanol, ethylene glycol and 1,2-propanediol, and the volume ratio of alcohol to water in the alcohol-water mixture is 1 to 3:

1. The concentration of the polypiperidinylpyrimidine solution is 1–5 mol / L; The concentration of the triple-bonded silane solution is 1–3 mol / L.

4. The preparation method according to claim 3, characterized in that, The alcohol solvents include one or more of methanol, anhydrous ethanol, propanol, ethylene glycol, and 1,2-propanediol; The non-alcoholic solvent comprises one or more of tetrahydrofuran, N,N-dimethylformamide, acetonitrile, ethyl acetate, and dimethyl sulfoxide.

5. The preparation method according to claim 4, characterized in that, Step 2) The addition rate is 1-20 mL / min, and the polypiperidinylpyrimidine solution is stirred during the addition process at a speed of 300-1000 rpm. The molar ratio of the polypiperidinylpyrimidine in the polypiperidinylpyrimidine solution to the 3-trimethylsilylpropynaldehyde in the triple bond silane solution is 1 to 5:

1.

6. The preparation method according to claim 4 or 5, characterized in that, The reaction temperature in step 2) is 60–120°C, and the reaction time is 3–24 h.

7. The preparation method according to claim 6, characterized in that, Step 3) The alcohol in the alcohol-water mixture includes one or more of methanol, anhydrous ethanol, propanol, ethylene glycol and 1,2-propanediol, and the volume ratio of alcohol to water in the alcohol-water mixture is 1 to 5:

1. The concentration of the polypiperidinylpyrimidine triple bond silane solution is 1–3 mol / L.

8. The preparation method according to claim 7, characterized in that, Step 4) The spraying rate is 10-100 mL / min, and the natural magnesia powder is stirred during the spraying process at a speed of 300-1000 rpm. The molar mass ratio of the polypiperidinylpyrimidine triple bond silane to the natural brucite powder in the polypiperidinylpyrimidine triple bond silane solution is 1-3 mol: 10 kg; The median particle size D of the natural brucite powder 50 The range is 0.9–4.5 μm.

9. The polypiperidinylpyrimidine-coupled brucite composite powder prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The median particle size D of the polypiperidinylpyrimidine-coupled brucite composite powder 50 The range is 1.0–4.6 μm.

10. The application of the polypiperidinylpyrimidine coupled brucite composite powder according to claim 9 in elastomers.

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