Natural hydroformylated silaza brucite composite powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of functional powder, and provides natural hydroformylated silaza brucite composite powder as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing an amino acid solution and an amino silane solution to obtain a mixed solution, and adding a natural aldehyde solution into silica powder to obtain composite silica powder; and mixing the composite silica powder, the natural brucite powder and the mixed solution. According to the invention, amino acid and natural aldehyde form a cross-linked chemical structure by using five-membered ring or six-membered ring amino silane, so that the oil absorption amount of the composite powder is reduced; a large number of conjugated aromatic rings in the natural aldehydes can improve the char forming property, the mechanical property and the flame retardant property in the combustion process; the natural aldehydes are loaded on the silica powder, so that in-situ cross-linking anchoring of amino acid between the silica powder and the natural brucite powder is promoted, and the chemical stability and the structural stability of the silaza brucite composite powder are improved; the organic-inorganic hybrid functional layer on the surface of the composite powder and the natural brucite in the composite powder have a synergistic effect.

Description

Technical Field

[0001] The present invention relates to the technical field of functional powders, and in particular to a natural formaldehyded silicate brucite composite powder, a preparation method thereof, and an application thereof. Background Art

[0002] There are many types of natural stone ores, with brucite and quartz being two of the most representative. These minerals are not only abundant in reserves and widely available, but also inherently environmentally friendly. Currently, natural stone powders produced through physical refinement suffer from surface structural defects and low purity, failing to fully demonstrate their functionality and limiting their application to low-value-added industries. Reconstructing and combining multiple natural stone powders could significantly increase their application value and effectively alleviate issues such as fossil energy depletion and high carbon emissions.

[0003] Currently, the development of natural brucite powder focuses on ultrafine processing and surface modification. However, due to process limitations of physical ultrafine processing, the particle size distribution of ultrafine natural brucite powder is wide and contains large coarse particles, which hinders dispersion and interfacial bonding during further processing. Surface modification using traditional surfactants such as silane coupling agents is not resistant to high temperatures and may even promote combustion during calcination (releasing large amounts of flammable molecular pyrolysis fragments), hindering the energy efficiency of natural brucite powder. Quartz powder offers significant advantages in hardness and heat resistance, significantly enhancing the particle size distribution, heat resistance, and ablation resistance of ultrafine natural brucite.

[0004] Therefore, it is urgent to develop the optimized reconstruction of quartz and natural brucite powder to achieve the improvement of the multiple functions of natural brucite composite powder. Summary of the Invention

[0005] The purpose of the present invention is to provide a natural formaldehyded silicate brucite composite powder and a preparation method and application thereof in view of the deficiencies in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing natural formaldehyded silicate brucite composite powder, comprising the following steps:

[0008] 1) mixing the amino acid solution and the aminosilane solution to obtain a mixed solution;

[0009] adding a natural aldehyde solution to silicon micropowder to obtain composite silicon micropowder;

[0010] 2) The composite silicon micropowder, natural brucite powder and the mixed solution are mixed to obtain natural formaldehyded silicon-mixed brucite composite powder.

[0011] Preferably, the concentration of the amino acid solution in step 1) is 0.5 to 3 mol / L, the amino acids in the amino acid solution include one or more of tyrosine, tryptophan, phenylalanine and histidine, and the solvent in the amino acid solution includes one or more of N,N-dimethylformamide, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol and propanol;

[0012] The concentration of the aminosilane solution is 1 to 5 mol / L, the aminosilane in the aminosilane solution comprises one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-diethylenetriaminopropylmethyldimethoxysilane and 3-diethylenetriaminopropyltrimethoxysilane, the solvent in the aminosilane solution comprises water, anhydrous ethanol and methanol, and the volume ratio of water, anhydrous ethanol and methanol is 1:1 to 5:0.5 to 1.5;

[0013] The concentration of the natural aldehyde solution is 0.2 to 2 mol / L, the natural aldehyde in the natural aldehyde solution is cinnamaldehyde, benzaldehyde or citronellal, and the solvent in the natural aldehyde solution includes one or more of N,N-dimethylformamide, ethyl acetate, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol and propanol.

[0014] Preferably, the molar ratio of the natural aldehyde, amino acid and aminosilane is 1:1-5:1-5;

[0015] The molar mass ratio of the natural aldehydes to the silicon powder is 1 mol: 1-10 kg.

[0016] Preferably, the mixing in step 1) is carried out under stirring conditions, the stirring speed is 900-1600 rpm, and the mixing time is 0.1-1 h.

[0017] Preferably, the addition in step 1) is carried out in the form of spraying at a rate of 10 to 100 mL / min; the silicon micropowder is stirred during the addition at a stirring speed of 600 to 1200 rpm.

[0018] Preferably, the particle size of the silicon micropowder in step 1) is 7000-9000 mesh, and the particle size of the natural brucite powder in step 2) is 5000-8000 mesh.

[0019] Preferably, in step 2), the mass ratio of the composite silicon micropowder to the natural brucite powder is 1:1-10.

[0020] Preferably, in step 2), the mixed solution is mixed with composite silicon powder and natural brucite powder in the form of a spray at a rate of 10 to 100 mL / min;

[0021] Step 2) The mixing is carried out under stirring conditions, and the stirring speed is 1000-2000 rpm.

[0022] The present invention also provides natural formaldehyded silica brucite composite powder prepared by the preparation method.

[0023] The present invention also provides application of the natural formaldehyded silica brucite composite powder in a hydroxybutyric acid-hydroxyvaleric acid copolymer composite substrate.

[0024] The beneficial effects of the present invention include the following:

[0025] 1) The natural aldehydes, amino acids, silicon micropowder, and natural brucite powder used in the present invention are all natural organic matter and natural inorganic minerals that are ubiquitous in nature. They are green and environmentally friendly, widely available, and cost-controlled. They can replace fossil energy and contribute to the sustainable development of a low-carbon economy.

[0026] 2) The present invention utilizes aminosilane to form a cross-linked chemical structure with amino acids and natural aldehydes, effectively anchoring them on the surface of silicon micropowder and natural brucite powder, reducing the surface energy and polarity of silicon micropowder and natural brucite powder, and reducing the oil absorption of the composite powder; aminosilane with a five-membered ring or a six-membered ring, containing a large amount of N and Si, is used to modify the natural brucite powder after reconstruction with the amino acid component, effectively improving the dispersibility of the composite powder in the PHBV matrix; the large amount of conjugated aromatic rings in natural aldehydes can improve the carbonization during the combustion process, which helps Physical barrier, exerting the condensed phase barrier effect, effectively inhibits the volatilization of smoke and combustible molecular chain fragments, while improving the mechanical properties and flame retardant properties of the composite powder in the PHBV matrix; the surface organic-inorganic hybrid functional layer of the composite powder and the inner layer of natural brucite have a synergistic effect. Natural brucite itself is an environmentally friendly flame retardant functional additive. During the combustion process, it can absorb heat and release a large amount of water vapor to form a heat-resistant MgO ceramic precursor, which effectively adheres to the surface of the burning material, enhancing physical barrier and improving the flame retardant properties of the composite substrate.

[0027] 3) The present invention loads natural aldehydes on silica micropowder with higher hardness, and can effectively homogenize the particle size of natural brucite powder through high-speed mechanical stirring, thereby improving the dispersibility of natural brucite powder. At the same time, the silica micropowder loaded with natural aldehydes can be dispersed on the outside of the natural brucite powder through high-speed stirring, providing a good foundation for further cross-linking coupling. Moreover, the silica micropowder, as a solid carrier of natural aldehydes, can promote the in-situ cross-linking and anchoring of amino acids between the silica micropowder and natural brucite powder, thereby improving the chemical stability and structural stability of the silica-brucite composite powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the natural formaldehyded silica brucite composite powder of the present invention;

[0029] Figure 2 This is a scanning electron microscope image of the natural formaldehyded silica brucite composite powder prepared in Example 1. DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing natural formaldehyded silicate brucite composite powder, comprising the following steps:

[0031] 1) mixing the amino acid solution and the aminosilane solution to obtain a mixed solution;

[0032] adding a natural aldehyde solution to silicon micropowder to obtain composite silicon micropowder;

[0033] 2) The composite silicon micropowder, natural brucite powder and the mixed solution are mixed to obtain natural formaldehyded silicon-mixed brucite composite powder.

[0034] In the present invention, the concentration of the amino acid solution in step 1) is preferably 0.5 to 3 mol / L, more preferably 1 to 2.5 mol / L, and more preferably 1.5 to 2 mol / L; the amino acids in the amino acid solution preferably include one or more of tyrosine, tryptophan, phenylalanine, and histidine, and the solvent in the amino acid solution preferably includes one or more of N,N-dimethylformamide, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol, and propanol;

[0035] The concentration of the aminosilane solution is preferably 1 to 5 mol / L, more preferably 2 to 4 mol / L, and more preferably 2.5 to 3.5 mol / L; the aminosilane in the aminosilane solution preferably comprises 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, One or more of N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-diethylenetriaminopropylmethyldimethoxysilane and 3-diethylenetriaminopropyltrimethoxysilane, wherein the solvent in the aminosilane solution preferably comprises water, anhydrous ethanol and methanol, and the volume ratio of water, anhydrous ethanol and methanol is preferably 1:1-5:0.5-1.5, more preferably 1:2-4:0.8-1.2, and more preferably 1:3:1;

[0036] The concentration of the natural aldehyde solution is preferably 0.2 to 2 mol / L, more preferably 0.5 to 1.5 mol / L, and more preferably 1 mol / L; the natural aldehyde in the natural aldehyde solution is preferably cinnamaldehyde, benzaldehyde or citronellal, and the solvent in the natural aldehyde solution preferably includes one or more of N,N-dimethylformamide, ethyl acetate, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol and propanol.

[0037] In the present invention, the cinnamaldehyde is preferably 4-hydroxy-3-methoxycinnamaldehyde and / or trans-3,5-dimethoxy-4-hydroxycinnamaldehyde; the benzaldehyde preferably comprises one or more of 4-hydroxybenzaldehyde, salicylaldehyde and vanillin; and the citronellal is preferably hydroxycitronellal.

[0038] In the present invention, the molar ratio of the natural aldehyde, amino acid and aminosilane is preferably 1:1-5:1-5, more preferably 1:1.5-4:2-4, and more preferably 1:3:3;

[0039] The molar mass ratio of the natural aldehyde to the silicon powder is preferably 1 mol: 1 to 10 kg, more preferably 1 mol: 3 to 8 kg, and even more preferably 1 mol: 5 kg.

[0040] In the present invention, when the molar mass ratio of natural aldehydes to silica micropowder is greater than 1 mol:1 kg, the natural aldehyde will be loaded on the surface of the silica micropowder too much. After reacting with the amino acid and aminosilane in the mixed solution, multiple silica-brucite composite powders will be wrapped together, which is not conducive to controlling the particle size of the silica-brucite composite powder and affecting the dispersion effect in the subsequent processing. When the molar mass ratio of natural aldehydes to silica micropowder is less than 1 mol:10 kg, the loading amount of natural aldehyde on the surface of the silica micropowder is too low, making it difficult to form a natural organic-inorganic hybrid functional layer on the surface of the natural brucite, resulting in partial exposure of the natural brucite and a significant reduction in the modification effect.

[0041] In the present invention, the mixing in step 1) is preferably carried out under stirring conditions, and the stirring speed is preferably 900-1600 rpm, more preferably 1000-1400 rpm, and more preferably 1200 rpm; the mixing time is preferably 0.1-1 h, more preferably 0.3-0.8 h, and more preferably 0.5 h.

[0042] In the present invention, the addition in step 1) is preferably in the form of a spray, and the spray rate is preferably 10 to 100 mL / min, more preferably 20 to 80 mL / min, and more preferably 50 mL / min; during the addition process, the silicon micropowder is preferably stirred, and the stirring speed is preferably 600 to 1200 rpm, more preferably 800 to 1000 rpm, and more preferably 900 rpm.

[0043] In the present invention, in step 1), the silicon micropowder is preferably preheated first, and then the natural aldehyde solution is added to the silicon micropowder; the preheating temperature is preferably 30-90°C, more preferably 60°C; the preheating time is preferably 0.1-0.5h, more preferably 0.2h.

[0044] In the present invention, in step 1), the natural aldehyde solution is added to the silicon micropowder. After the addition is completed, stirring is preferably continued to obtain composite silicon micropowder; the speed of continued stirring is preferably 600-1200 rpm, more preferably 800-1000 rpm, and more preferably 900 rpm; the time for continued stirring is preferably 0.1-1 h, more preferably 0.3-0.8 h, and more preferably 0.5 h.

[0045] In the present invention, the particle size of the silicon micropowder in step 1) is preferably 7000-9000 mesh, more preferably 7500-8500 mesh, and more preferably 8000 mesh; the particle size of the natural brucite powder in step 2) is preferably 5000-8000 mesh, more preferably 6000-7500 mesh, and more preferably 7000 mesh.

[0046] In the present invention, the mass ratio of the composite silicon powder to the natural brucite powder in step 2) is preferably 1:1-10, more preferably 1:3-8, and even more preferably 1:5.

[0047] In the present invention, the mixed solution in step 2) is preferably mixed with the composite silicon powder and natural brucite powder in the form of a spray, and the spraying rate is preferably 10 to 100 mL / min, more preferably 20 to 80 mL / min, and more preferably 50 mL / min;

[0048] In step 2), the mixing is preferably carried out under stirring conditions, and the stirring speed is preferably 1000 to 2000 rpm, more preferably 1200 to 1800 rpm, and more preferably 1500 rpm.

[0049] In the present invention, in step 2) during the process of mixing the mixed liquid with the composite silicon micropowder and the natural brucite powder in the form of a spray, the mixed powder of the composite silicon micropowder and the natural brucite powder is preferably heated; the heating is stopped when the temperature reaches preferably 80 to 100° C., more preferably 90° C.; the heating rate is preferably 3 to 10° C. / min, more preferably 5 to 8° C. / min.

[0050] In the present invention, after the mixing is completed in step 2), the mixture is preferably continued to be stirred, then cooled and stirred, and then dusted and dried in sequence to obtain a natural formaldehyded silicate brucite composite powder; the speed of the continued stirring is preferably 1000-2000 rpm, more preferably 1200-1800 rpm, more preferably 1500 rpm; the time of continued stirring is preferably 10-45 min, more preferably 15-35 min, more preferably 25 min; the cooling and stirring is preferably carried out after cooling to room temperature, and the speed of the cooling and stirring is preferably 1000-2000 rpm, more preferably 1200-1800 rpm, more preferably 1500 rpm; the time of cooling and stirring is preferably 0. 1 to 0.5h, more preferably 0.2 to 0.4h, more preferably 0.3h; the dust removal is preferably carried out by a cyclone separator, and the air inlet rate of the cyclone separator is preferably 5 to 18m / s, more preferably 8 to 15m / s, more preferably 12m / s; the rotation speed of the cyclone separator is preferably 300 to 1000rpm, more preferably 500 to 800rpm, more preferably 700rpm; the power of the cyclone separator is preferably 100 to 500W, more preferably 200 to 400W, more preferably 300W; the dust removal time is preferably 1 to 30s, more preferably 2 to 20s; the drying is preferably hot air drying, and the air inlet volume of the hot air drying is preferably 300 to 900m 3 / h, more preferably 500 to 700 m 3 / h, more preferably 600m 3 / h; the hot air drying temperature is preferably 90 to 130°C, more preferably 100 to 120°C, more preferably 110°C; the hot air drying time is preferably 0.1 to 0.3h, more preferably 0.2h.

[0051] The present invention also provides natural formaldehyded silica brucite composite powder prepared by the preparation method.

[0052] The present invention also provides application of the natural formaldehyded silica brucite composite powder in a hydroxybutyric acid-hydroxyvaleric acid copolymer composite substrate.

[0053] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] The silicon micropowder used in the embodiments and comparative examples of the present invention is GS-8000 produced by Jiangxi Guangyuan Chemical Co., Ltd., and the natural brucite powder is GY-6000 produced by Jiangxi Guangyuan Chemical Co., Ltd.

[0055] Example 1

[0056] 3 mol of tyrosine was dissolved in a mixture of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide (the volume ratio of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide in the mixture was 3:4:1) to obtain a 2 mol / L amino acid solution. 2 mol of 3-aminopropylmethyldimethoxysilane was dissolved in a mixture of purified water, anhydrous ethanol, and methanol (the volume ratio of purified water, anhydrous ethanol, and methanol in the mixture was 1:3:1) to obtain a 5 mol / L aminosilane solution. The amino acid solution and aminosilane solution were stirred at 1200 rpm at room temperature for 1 hour to obtain a mixed solution. 1 mol of 4-hydroxy-3-methoxycinnamaldehyde was dissolved in tetrahydrofuran to obtain a 2 mol / L natural aldehyde solution. 1 kg of 8000-mesh silica powder (SP) was preheated in a high-speed blender at 60°C and 900 rpm for 0.2 hours. The natural aldehyde solution was then sprayed onto the silica powder at a rate of 10 mL / min. Stirring was continued at 900 rpm during the spraying process. After the spraying was complete, stirring was continued at 900 rpm for 0.5 h to obtain composite silica powder.

[0057] At 35°C, 1 kg of natural brucite powder (NBP) with a particle size of 6000 mesh was placed in a high-speed blender and stirred at a speed of 2000 rpm. First, 1 kg of composite silicon micropowder was added to the high-speed blender, and then the mixture was added to the high-speed blender in the form of a spray at a spray rate of 50 mL / min. During the spray addition process, stirring was continued at a speed of 2000 rpm, and the mixed powder was controlled to heat up to 90°C at a heating rate of 5°C / min and then stopped heating. After the spraying was completed, stirring was continued at a speed of 2000 rpm for 25 minutes, then cooled to room temperature, and stirred at a speed of 2000 rpm for 0.3 hours at room temperature. The mixed powder was then placed in a cyclone separator with an air inlet rate of 5 m / s, a speed of 800 r / min, and a power of 500 W for dust removal for 15 seconds. The mixed powder after dust removal was placed at 110°C, 900 m 3 / h air flow rate for hot air drying for 0.1h to obtain natural formaldehyde silica brucite composite powder (SP-NOM-NBP).

[0058] Figure 1 The figure is a schematic structural diagram of the natural formaldehyde silicate brucite composite powder of the present invention. Figure 1 It can be seen that the natural formaldehyded silicate brucite composite powder consists of an outer organic-inorganic hybrid functional layer and an inner natural brucite layer. It is a typical organic-inorganic hybrid composite powder reconstructed from multiple natural minerals.

[0059] Figure 2 This is a scanning electron microscope image of the natural formaldehyded silicate brucite composite powder prepared in Example 1. Figure 2 It can be seen that a composite functional layer of natural aldehyde-modified silica powder is attached to the surface of the composite powder, and the composite functional layer is evenly covered on the surface of the natural brucite powder to form a good composite structure of silica-brucite.

[0060] Example 2

[0061] Dissolve 1 mol of tyrosine in a mixture of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide (the volume ratio of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide in the mixture is 3:4:1) to obtain an amino acid solution with a concentration of 3 mol / L. Dissolve 1 mol of 3-aminopropylmethyldiethoxysilane in a mixture of purified water, anhydrous ethanol, and methanol (the volume ratio of purified water, anhydrous ethanol, and methanol in the mixture is 1:1:1) to obtain an aminosilane solution with a concentration of 2.5 mol / L. The amino acid solution and aminosilane solution are stirred at 900 rpm at room temperature for 0.5 h to obtain a mixed solution. Dissolve 0.2 mol of trans-3,5-dimethoxy-4-hydroxycinnamaldehyde in tetrahydrofuran to obtain a natural aldehyde solution with a concentration of 0.2 mol / L. Preheat 1 kg of 8000-mesh silica powder in a high-speed blender at 30°C and 1200 rpm for 0.5 h. The natural aldehyde solution was then sprayed onto the silica powder at a rate of 100 mL / min. Stirring was continued at 1200 rpm during the spraying process. After the spraying was complete, stirring was continued at 1200 rpm for 0.1 h to obtain composite silica powder.

[0062] At 25°C, 5kg of natural brucite powder with a particle size of 6000 mesh was placed in a high-speed mixer and stirred at a speed of 1000rpm. First, 1kg of composite silicon micropowder was added to the high-speed mixer, and then the mixture was added to the high-speed mixer in the form of a spray at a spray rate of 10mL / min. During the spray addition process, stirring was continued at a speed of 1000rpm, and the mixed powder was controlled to heat up to 80°C at a heating rate of 3°C / min and then stopped heating. After the spraying was completed, stirring was continued at a speed of 1000rpm for 10min, then cooled to room temperature, and stirred at a speed of 1000rpm for 0.5h at room temperature. The mixed powder was then placed in a cyclone separator with an air inlet rate of 12m / s, a speed of 300r / min, and a power of 300W for dust removal for 1s. The mixed powder after dust removal was placed at 90°C, 700m 3 The mixture was dried with hot air for 0.3 h at an air inlet volume of / h to obtain natural formaldehyded silica brucite composite powder.

[0063] Example 3

[0064] 3 mol of histidine was dissolved in a mixture of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide (the volume ratio of anhydrous ethanol, tetrahydrofuran, and dimethyl sulfoxide in the mixture was 3:4:1) to obtain a 1 mol / L amino acid solution. 5 mol of 3-aminopropyltrimethoxysilane was dissolved in a mixture of purified water, anhydrous ethanol, and methanol (the volume ratio of purified water, anhydrous ethanol, and methanol in the mixture was 1:5:1) to obtain a 1 mol / L aminosilane solution. The amino acid solution and aminosilane solution were stirred at 1600 rpm for 0.1 hour at room temperature to obtain a mixed solution. 2 mol of salicylaldehyde was dissolved in tetrahydrofuran to obtain a 1 mol / L natural aldehyde solution. 20 kg of 8000-mesh silica powder was placed in a high-speed blender and preheated at 90°C at 600 rpm for 0.1 hour. The natural aldehyde solution was then sprayed onto the silica powder at a rate of 50 mL / min. Stirring was continued at 600 rpm during the spraying process. After the spraying was complete, stirring was continued at 600 rpm for 1 hour to obtain composite silica powder.

[0065] At 60°C, 10kg of natural brucite powder with a particle size of 6000 mesh was placed in a high-speed mixer and stirred at a speed of 1500rpm. First, 1kg of composite silicon micropowder was added to the high-speed mixer, and then the mixture was added to the high-speed mixer in the form of a spray at a spray rate of 100mL / min. During the spray addition process, stirring was continued at a speed of 1500rpm, and the mixed powder was controlled to heat up to 100°C at a heating rate of 10°C / min and then stopped heating. After the spraying was completed, stirring was continued at a speed of 1500rpm for 45min, then cooled to room temperature, and stirred at a speed of 1500rpm for 0.1h at room temperature. The mixed powder was then placed in a cyclone separator with an air inlet rate of 18m / s, a speed of 1000r / min, and a power of 100W for dust removal for 30s. The mixed powder after dust removal was placed at 130°C, 300m 3 / h air flow rate for hot air drying for 0.2h to obtain natural formaldehyded silica brucite composite powder.

[0066] Comparative Example 1

[0067] The addition amount of 4-hydroxy-3-methoxycinnamaldehyde in Example 1 was modified to 0.1 mol, and the rest was the same as in Example 1.

[0068] Comparative Example 2

[0069] The addition amount of 4-hydroxy-3-methoxycinnamaldehyde in Example 1 was modified to 6 mol, and the rest was the same as in Example 1.

[0070] The performance tests were carried out on the composite powders prepared in Examples 1 to 3, Comparative Examples 1 to 2, and GY-6000 natural brucite powder. The oil absorption was tested according to DB / T5211.15-2014, and the particle size distribution (D 90 / D 10 ) Dynamic light scattering was used for testing; the powder was pressed into 1.5 mm thick tablets at 25 MPa for 3 minutes, and contact angle measurements were performed according to GB / T 24368-2009. The test results are shown in Table 1.

[0071] Table 1 Performance test results of composite powder

[0072]

[0073] As shown in Table 1, the contact angles of the composite powders of Examples 1 to 3 are significantly higher than those of GY-6000 natural brucite powder, and the oil absorption is significantly lower than that of GY-6000 natural brucite powder. This result indicates that the organic-inorganic hybrid reconstruction method of the present invention can effectively shield the surface hydroxyl groups of natural brucite, significantly reduce the surface polarity of natural brucite, facilitate subsequent processing and dispersion, and is not easy to absorb moisture during storage, making it suitable for long-term storage. Compared with Examples 1 to 3, the contact angles of Comparative Examples 1 to 2 decreased to varying degrees, the oil absorption increased to varying degrees, and the particle size distribution expanded. The results show that when the molar mass ratio of natural aldehydes to silicon micropowder is less than 1 mol:10 kg, the amount of natural aldehyde added is too low and the modification effect is general. When the molar mass ratio of natural aldehydes to silicon micropowder is higher than 1 mol:1 kg, the amount of natural aldehyde added is too high. Excessive natural aldehydes may cause multiple brucite particles to be wrapped together, which is not conducive to the control of the particle size of the composite powder. In addition, functional outer layers such as natural aldehydes may fall off or peel off during processing, affecting the modification effect. The present invention, by reasonably controlling the dosage ratio of natural aldehydes to silicon micropowder, can better modify the surface of natural brucite powder, significantly improve the contact angle and oil absorption of the composite powder, and well control the particle size distribution, which is conducive to the dispersion of the composite powder in the composite substrate.

[0074] Application Example 1

[0075] Place hydroxybutyric acid-hydroxyvaleric acid copolymer (PHBV) and polybutylene adipate / terephthalate (PBAT) in a blast drying oven and dry overnight at 70°C. Take 80 parts by mass of PHBV and 20 parts by mass of PBAT for extrusion granulation (the extrusion temperature of each section is 170°C, 180°C, 190°C, 200°C, 210°C, and the screw speed is 30r / min) to obtain PHBV composite substrate masterbatch. 15 parts by mass of the composite powder prepared in Example 1 is mixed with the PHBV composite substrate masterbatch, and then 0.25 parts by mass of antioxidant 1076, 0.25 parts by mass of antioxidant 1010, 0.5 parts by mass of silicone grease (DOW 111), extrusion granulation was carried out (the extrusion temperature of each section was 170°C, 180°C, 190°C, 200°C, and 210°C, and the screw speed was 30r / min) to obtain a composite masterbatch.

[0076] Application Example 2

[0077] The composite powder of Application Example 1 was replaced by the composite powder of Example 2, and the rest was the same as Application Example 1.

[0078] Application Example 3

[0079] The composite powder of Application Example 1 was replaced by the composite powder of Example 3, and the rest was the same as Application Example 1.

[0080] Comparative Application Example 1

[0081] The composite powder of Application Example 1 was replaced by the composite powder of Comparative Example 1, and the rest was the same as Application Example 1.

[0082] Comparative Application Example 2

[0083] The composite powder of Application Example 1 was replaced by the composite powder of Comparative Example 2, and the rest was the same as Application Example 1.

[0084] Comparative Application Example 3

[0085] The composite powder in Application Example 1 was replaced with GY-6000 natural brucite powder, and the rest was the same as in Application Example 1.

[0086] The composite masterbatches of Application Examples 1 to 3 and Comparative Application Examples 1 to 3 were prepared into test samples and subjected to performance tests. The test results are shown in Table 2.

[0087] The tensile strength test was carried out according to GB / T 1010-1992 at a tensile rate of 2 mm / min.

[0088] Limiting Oxygen Index testing was performed in accordance with ISO 4589-2:2017.

[0089] The carbon residue rate test method is: in a nitrogen atmosphere, start from room temperature and increase the temperature at 10℃ / min to 600℃, and calculate the ratio of the carbon residue mass to the initial mass, which is the carbon residue rate.

[0090] The rheological properties test method is as follows: at 180°C, the scanning frequency of the dynamic rheological shear instrument is 0.1 to 100 rad / s, and the test samples are tested at shear rates of 0.1s -1 and 10s -1 Shear viscosity at .

[0091] Table 2 Performance test results of composite samples

[0092]

[0093] As can be seen from Table 2, adding the natural formaldehyded silica brucite composite powders of Examples 1 to 3 of the present invention to the PHBV composite substrate can significantly improve the tensile strength of the substrate, and the carbon residue rate at 600°C and the limiting oxygen index are also significantly improved compared to the natural brucite powder without any modification, thereby effectively improving the flame retardant properties of the composite substrate; the composite substrate has a flame retardant property of 0.1s -1 The shear viscosity in the low frequency region also increased significantly compared to the natural brucite powder without any modification. -1 The shear viscosity in the high-frequency region is significantly lower than that in the low-frequency region, demonstrating a significant "shear thinning" effect. This indicates that the natural formaldehyde-modified silica-bruccite ​​composite powder of the present invention, when applied to a PHBV composite substrate, helps reduce internal friction loss at high temperatures and improves fluidity. In contrast, the composite powders obtained by modifying natural brucite powder with an unreasonable ratio of natural formaldehyde to silica powder in Examples 1 and 2 exhibit a reduced degree of shear thinning in the PHBV composite substrate, resulting in limited improvement in the composite substrate's fluidity. These results demonstrate that the composite powders obtained by surface-modifying natural brucite powder with organic matter, such as natural aldehydes, amino acids, and silica powder, can improve the mechanical properties, flame retardancy, and processing fluidity of the PHBV composite substrate.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a natural formaldehyded silicate brucite composite powder, characterized in that: The following steps are included: 1) mixing the amino acid solution and the aminosilane solution to obtain a mixed solution; adding a natural aldehyde solution to silicon micropowder to obtain composite silicon micropowder; 2) The composite silicon micropowder, natural brucite powder and the mixed solution are mixed to obtain natural formaldehyded silicon-mixed brucite composite powder.

2. The preparation method according to claim 1, characterized in that Step 1) The concentration of the amino acid solution is 0.5 to 3 mol / L, the amino acids in the amino acid solution include one or more of tyrosine, tryptophan, phenylalanine, and histidine, and the solvent in the amino acid solution includes one or more of N,N-dimethylformamide, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol, and propanol; The concentration of the aminosilane solution is 1 to 5 mol / L, the aminosilane in the aminosilane solution comprises one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-diethylenetriaminopropylmethyldimethoxysilane and 3-diethylenetriaminopropyltrimethoxysilane, the solvent in the aminosilane solution comprises water, anhydrous ethanol and methanol, and the volume ratio of water, anhydrous ethanol and methanol is 1:1 to 5:0.5 to 1.5; The concentration of the natural aldehyde solution is 0.2 to 2 mol / L, the natural aldehyde in the natural aldehyde solution is cinnamaldehyde, benzaldehyde or citronellal, and the solvent in the natural aldehyde solution includes one or more of N,N-dimethylformamide, ethyl acetate, tetrahydrofuran, acetonitrile, methanol, anhydrous ethanol and propanol.

3. The preparation method according to claim 2, characterized in that The molar ratio of the natural aldehyde, amino acid and aminosilane is 1:1-5:1-5; The molar mass ratio of the natural aldehydes to the silicon powder is 1 mol: 1-10 kg.

4. The preparation method according to claim 3, characterized in that The mixing in step 1) is carried out under stirring conditions, the stirring speed is 900 to 1600 rpm, and the mixing time is 0.1 to 1 hour.

5. The preparation method according to claim 4, characterized in that Step 1) The addition is carried out in the form of spraying at a rate of 10 to 100 mL / min; the silicon micropowder is stirred during the addition at a stirring speed of 600 to 1200 rpm.

6. The preparation method according to claim 4 or 5, characterized in that The particle size of the silicon micropowder in step 1) is 7000-9000 mesh, and the particle size of the natural brucite powder in step 2) is 5000-8000 mesh.

7. The preparation method according to claim 6, characterized in that In step 2), the mass ratio of the composite silicon micropowder to the natural brucite powder is 1:1-10.

8. The preparation method according to claim 7, characterized in that Step 2) the mixed solution is mixed with composite silicon powder and natural brucite powder in the form of a spray at a rate of 10 to 100 mL / min; Step 2) The mixing is carried out under stirring conditions, and the stirring speed is 1000-2000 rpm.

9. Natural formaldehyde brucite composite powder prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the natural formaldehyded silica brucite composite powder according to claim 9 in a hydroxybutyric acid-hydroxyvaleric acid copolymer composite substrate.

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