Preparation method and application of phytic acid-melamine / montmorillonite delustering agent

Abstract

The invention discloses a preparation method and application of a phytic acid-melamine / montmorillonite delustering agent, melamine is ionized through phytic acid, then melamine cations enter montmorillonite interlayers, interlaminar sodium ions or calcium ions which are obtained through exchange and phytic acid anions form ionic bonds, and the ionic bonds are formed by sodium ions or calcium ions and the phytic acid anions. Melamine and phytic acid are combined with montmorillonite lamellas to form a stable macromolecular core-shell structure, and the matting agent with the flame retardant effect is obtained. According to the preparation method disclosed by the invention, the interlayer spacing of the montmorillonite is expanded by utilizing cation exchange, and then the interlayer spacing of the montmorillonite is further expanded by utilizing phytic acid self-assembly, so that the layered stripping of the montmorillonite nanosheets is finally realized, the dispersity of the delustering agent is improved, and the effect of double coating layers of melamine and phytic acid is achieved; the heat stability and the flame retardant property are remarkably improved, and the problems that an existing delustering agent is single in function, unstable in dispersity and flame retardant effect and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of multifunctional matting agents, and more specifically, relates to a preparation method and application of a phytic acid-melamine / montmorillonite matting agent. Background Art

[0002] With the continuous improvement of the requirements for material properties in modern industry, especially in the fields of coatings, plastics, textiles, etc., the regulation of optical properties has become increasingly important. As a key additive, matting agents can adjust the surface gloss of materials, reduce reflected light and improve the visual effect, and have been widely used in the surface treatment of various materials. However, traditional inorganic powder matting agents have significant problems. For example, their particles are prone to agglomeration, resulting in poor dispersibility, which in turn affects the matting effect.

[0003] Montmorillonite, as a layered silicate mineral, has a high specific surface area and a layered structure. The layered structure of montmorillonite can effectively carry functional molecules, and it has certain flame retardancy. Therefore, it can be used as a matting agent carrier for expanding flame retardancy. However, montmorillonite still needs to be improved in terms of matting effect, dispersibility, stability and flame retardant performance.

[0004] Phytic acid is a phosphorus-containing bio-based material discovered in recent years. During the combustion process, phosphoric acid and polyphosphoric acid formed by the decomposition of phytic acid can effectively flame-retard the base material, so it is regarded as an excellent natural flame retardant. In the patent CN116731394A, "A Flame Retardant and Its Preparation Method and Application", it is disclosed that melamine is mixed with water to prepare a melamine suspension, and then phytic acid is added to the melamine suspension for heat treatment. After drying, melamine phytate is obtained. Then, hydroxyapatite, melamine phytate, and a catalyst are added to water. After stirring and heat treatment, the flame retardant is obtained. The flame retardant prepared by this patent uses the abundant hydroxyl groups on the surface of hydroxyapatite after hydroxylation as the reaction sites for the phosphate groups on phytic acid, realizing the chemical bond combination between hydroxyapatite and melamine phytate, eliminating the compatibility problem between inorganic and organic substances, and enhancing the synergistic flame retardant and toughening effects between the two. At the same time, when the hydroxyl groups on the surface of hydroxyapatite and the acidic groups in melamine phytate are heated, they can dehydrate to form carbon, thus promoting the formation of a carbon layer and further inhibiting the combustion dripping of polypropylene. The catalysts potassium methoxide and sodium methoxide used in this patent will decompose into methanol and sodium hydroxide, potassium hydroxide in their reaction aqueous solution. Under their reaction conditions, methanol will volatilize quickly, and the strong base will only react with phytic acid and hydroxyapatite to eliminate the hydroxyl or carboxyl groups on their surfaces and sodiumize them, but it cannot make hydroxyapatite and melamine phytate react to produce chemical bonds. Carbamidine and urease will also compete with melamine for phytic acid in the aqueous solution, resulting in low grafting efficiency and unstable flame retardant effect. And although this patent first synthesizes melamine phytate and then makes this insoluble macromolecular melamine phytate react and combine with hydroxyapatite, enhancing the compatibility and flame retardant synergy of hydroxyapatite, it is difficult to effectively utilize the exfoliable characteristics of the lamellar structure of montmorillonite to improve the dispersibility when grafting macromolecular melamine phytate onto montmorillonite. Therefore, the surface grafting of melamine phytate has limited effects on the dispersibility, stability, flame retardancy, etc. of montmorillonite. Summary of the Invention

[0005] In order to overcome the problems of low grafting efficiency, poor stability, and limited improvement effect when grafting montmorillonite with existing melamine phytate, the present invention provides a preparation method and application of a phytic acid-melamine / montmorillonite matting agent.

[0006] The present invention is realized through the following technical solutions:

[0007] A preparation method of a phytic acid-melamine / montmorillonite matting agent, the steps include:

[0008] S1. Disperse montmorillonite in deionized water to obtain a montmorillonite lamellar dispersion;

[0009] S2. Dissolve phytic acid and melamine in water, heat and stir until melamine is dissolved to obtain an ionized melamine solution of phytic acid.

[0010] S3. Mix the ionized melamine solution of phytic acid and the montmorillonite dispersion, react, and complete the macromolecular self-assembly of phytic acid and melamine with the montmorillonite nanosheets as the core to form an aqueous solution of a phytic acid-melamine / montmorillonite matting agent.

[0011] Further, the montmorillonite is at least one of raw montmorillonite, sodium-based montmorillonite, and calcium-based montmorillonite.

[0012] Further, the ultrasonic treatment of the montmorillonite in water is 0.5 - 2.5 h.

[0013] Further, the mass ratio of the total mass of phytic acid and melamine to the mass of montmorillonite is 70 - 100:1.

[0014] Further, the molar ratio of phytic acid to melamine is 4 - 9:3.

[0015] Further, the heating temperature in step S2 is 95 - 98 °C, and the stirring time is 0.5 - 3.5 h.

[0016] Further, the reaction in step S3 includes heating and stirring, and then cooling to room temperature for self-assembly reaction.

[0017] Further, the heating temperature is 50 - 115 °C, and the stirring time is 0.5 - 3 h; the self-assembly reaction time is 1 - 24 h.

[0018] Further, the method further includes drying the aqueous solution of the phytic acid-melamine / montmorillonite matting agent to obtain a solid phytic acid-melamine / montmorillonite matting agent.

[0019] Further, the application of the matting agent prepared by the preparation method of the phytic acid-melamine / montmorillonite matting agent in coatings, plastics, and textiles.

[0020] Compared with the prior art, the beneficial effects are:

[0021] In the present invention, the ionization of melamine by phytic acid effectively overcomes the insolubility of melamine in water, enabling it to enter the interlayer of montmorillonite for cation exchange, expanding the interlayer spacing of montmorillonite. Then, the sodium ions or calcium ions in the interlayer of montmorillonite exchanged by melamine form ionic bonds with the phytic acid anions. The self-assembly of phytic acid further expands the interlayer spacing of montmorillonite and achieves the effect of a double coating layer of melamine and phytic acid. Finally, the exfoliation of montmorillonite nanosheets is realized. The montmorillonite at the nanosheet level not only improves the dispersibility of montmorillonite but also endows it with excellent matting properties and flame retardancy.

[0022] Combining the synergistic flame retardancy of montmorillonite, phytic acid and melamine, phosphorus-containing compounds are released during combustion by the decomposition of polyamide groups, promoting the carbonization of organic substances; the nano-sheet barrier effect of montmorillonite can promote the formation of a phosphorus-carbon composite between the polymer matrix and polyamide, further forming a continuous and dense carbon layer; at the same time, melamine releases non-combustible gases such as NH3, diluting the concentration of combustible gases and taking away heat, forming a gas protection layer.

[0023] The supramolecular self-assembly technology adopted in the present invention enables melamine and phytic acid to combine with montmorillonite sheets, forming a stable macromolecular core-shell structure and a matting agent with flame retardant effects, enabling it to be evenly dispersed, thereby significantly improving the dispersibility and optical properties of the matting agent. This matting agent not only has excellent visible light matting effect and ultraviolet matting effect, but also has significantly improved thermal stability and flame retardant performance. The raw materials of the matting agent described in the present invention are easily available and the preparation method is simple, which can reduce the preparation cost of the matting agent and has promotional value. Description of the Drawings

[0024] Figure 1 It is a vertical combustion test diagram of PVA and PVA / MMT@PAMEL composite films. Detailed Embodiments

[0025] The following further explains and clarifies with reference to embodiments, but the specific embodiments do not limit the present invention in any form. Unless otherwise specified, the methods and equipment used in the embodiments are conventional methods and equipment in the art, and the raw materials used are all conventional commercially available raw materials.

[0026] Example 1

[0027] This example provides a flame retardant matting agent, and the preparation steps include:

[0028] S1. Swell 1 g of raw montmorillonite in 1500 g of water for 24 h, and then use high-speed mechanical stirring for 1 h and ultrasonic treatment for 1 h on the swollen montmorillonite solution to obtain a dispersion of montmorillonite sheets with a wafer thickness of 0.9 nm -

[0029] 5 μm thick.

[0030] S2. Dissolve 0.4 mol of phytic acid and 0.3 mol of melamine in water, heat up to 95 °C, and stir for 1 h until the melamine is completely dissolved to obtain a phytic acid-melamine mixed solution.

[0031] S3. Add the phytic acid melamine mixed solution prepared in step S2 to the montmorillonite platelet dispersion prepared in step S1, and keep it warm and stirred at 65 °C for 1 h. Finally, cool the mixed solution to room temperature. After 12 h, phytic acid, melamine and sodium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite, and an aqueous solution of the matting agent is prepared.

[0032] Example 2

[0033] This example provides a matting agent with flame retardancy, and the preparation steps include:

[0034] S1. Swell 1.5 g of raw montmorillonite in 2500 g of water for 24 h, and then use high-speed mechanical stirring for 1.5 h and ultrasonic treatment for 1.5 h on the swollen montmorillonite solution to prepare a nano-level raw montmorillonite platelet dispersion with a wafer thickness of 0.9 nm - 5 μm peeled into the aqueous dispersion.

[0035] S2. Dissolve 0.5 mol of phytic acid and 0.3 mol of melamine in water, heat up to 95 °C, and stir for 1.5 h until the melamine is completely dissolved to prepare a phytic acid melamine mixed solution.

[0036] S3. Add the phytic acid melamine mixed solution prepared in step S2 to the raw montmorillonite platelet dispersion prepared in step S1, and keep it warm and stirred at 75 °C for 1.5 h. Finally, cool the mixed solution to room temperature. After 15 h, phytic acid, melamine and sodium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite.

[0037] S4. Put the phytic acid-melamine macromolecule / montmorillonite composite prepared in step S3 into an oven and dry it at 75 °C for 14 h to prepare a phytic acid-melamine macromolecule / montmorillonite composite matting agent, that is, a matting agent with flame retardant properties.

[0038] Example 3

[0039] This example provides a matting agent with flame retardancy, and the preparation steps include:

[0040] S1. Swell 1.5 g of sodium montmorillonite in 3000 g of water for 24 h, and then use high-speed mechanical stirring for 2 h and ultrasonic treatment for 2 h on the swollen montmorillonite solution to prepare a sodium montmorillonite platelet dispersion with a wafer thickness of 0.9 nm - 5 μm peeled into the aqueous dispersion.

[0041] S2. Dissolve 0.6 mol of phytic acid and 0.3 mol of melamine in water, heat up to 98 °C, and stir for 2 h until the melamine is completely dissolved to prepare a phytic acid melamine mixed solution.

[0042] S3. Add the phytic acid-melamine mixed solution prepared in step S2 to the nano-scale sodium montmorillonite platelet dispersion prepared in step S1, and keep stirring at 85 °C for 1.5 h. Finally, cool the mixed solution to room temperature. After 24 h, phytic acid, melamine and sodium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite material.

[0043] S4. Put the phytic acid-melamine macromolecule / montmorillonite prepared in step S3 into an oven and dry it at 85 °C for 16 h to obtain a phytic acid-melamine macromolecule / montmorillonite matting agent, that is, a matting agent with flame retardant properties.

[0044] Example 4

[0045] This example provides a matting agent with flame retardant properties. The preparation steps include:

[0046] S1. Swell 2 g of calcium montmorillonite in 3500 g of water for 24 h, and then use high-speed mechanical stirring for 1.5 h and ultrasonic treatment for 1.5 h on the swollen montmorillonite solution to obtain a sodium montmorillonite platelet dispersion with a wafer thickness of 0.9 nm - 5 μm peeled into the aqueous dispersion.

[0047] S2. Dissolve 0.7 mol of phytic acid and 0.3 mol of melamine in water, heat up to 98 °C, and stir for 2.5 h until the melamine is completely dissolved to obtain a phytic acid-melamine mixed solution.

[0048] S3. Add the phytic acid-melamine mixed solution prepared in step S2 to the calcium montmorillonite platelet dispersion prepared in step S1, and keep stirring at 95 °C for 2 h. Finally, cool the mixed solution to room temperature. After 18 h, phytic acid, melamine and calcium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite material.

[0049] S4. Put the phytic acid-melamine macromolecule / montmorillonite composite material prepared in step S3 into an oven and dry it at 95 °C for 18 h to obtain a phytic acid-melamine macromolecule / montmorillonite matting agent, that is, a matting agent with flame retardant properties.

[0050] Example 5

[0051] This example provides a matting agent with flame retardant properties. The preparation steps include:

[0052] S1. Swell 2.5 g of calcium montmorillonite in 4500 g of water for 24 h, and then use high-speed mechanical stirring for 2.5 h and ultrasonic treatment for 2 h on the swollen montmorillonite solution to obtain a calcium montmorillonite platelet dispersion with a wafer thickness of 0.9 nm - 5 μm peeled into the aqueous dispersion.

[0053] S2. Dissolve 0.8 mol of phytic acid and 0.3 mol of melamine in water, heat up to 98 °C, and stir for 3 h until the melamine is completely dissolved to obtain a phytic acid-melamine mixed solution.

[0054] S3. Add the phytic acid-melamine mixed solution prepared in step S2 to the calcium montmorillonite lamellar dispersion prepared in step S1, keep it warm and stir at 105 °C for 2.5 h. Finally, cool the mixed solution to room temperature. After 21 h, phytic acid, melamine and calcium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite.

[0055] S4. Put the phytic acid-melamine macromolecule / montmorillonite composite prepared in step S3 into an oven and dry it at 105 °C for 20 h to obtain a phytic acid-melamine macromolecule / montmorillonite matting agent, that is, a matting agent with flame retardant properties.

[0056] Example 6

[0057] This example provides a matting agent with flame retardant properties. The preparation steps include:

[0058] S1. Swell 3 g of calcium montmorillonite in 5000 g of water for 24 h, and then use high-speed mechanical stirring for 3 h and ultrasonic treatment for 2.5 h on the swollen montmorillonite solution to obtain a calcium montmorillonite lamellar dispersion with the wafer thickness peeled into 0.9 nm - 5 μm thick in the aqueous dispersion.

[0059] S2. Dissolve 0.9 mol of phytic acid and 0.3 mol of melamine in a certain amount of water, heat up to 98 °C, and stir for 3.5 h until the melamine is completely dissolved to obtain a phytic acid-melamine mixed solution.

[0060] S3. Add the phytic acid-melamine mixed solution prepared in step S2 to the calcium montmorillonite lamellar dispersion prepared in step S1, keep it warm and stir at 115 °C for 3 h. Finally, cool the mixed solution to room temperature. After 24 h, phytic acid, melamine and calcium montmorillonite complete supramolecular self-assembly to form a phytic acid-melamine macromolecule / montmorillonite composite.

[0061] S4. Put the phytic acid-melamine macromolecule / montmorillonite composite prepared in step S3 into an oven and dry it at 115 °C for 22 h to obtain a phytic acid-melamine macromolecule / montmorillonite matting agent, that is, a matting agent with flame retardant properties.

[0062] Test the matting performance, thermal stability and flame retardant performance of the matting agents prepared in Examples 1 - 6. The test results are as follows:

[0063] (1) Matting performance

[0064] The matting agents prepared in Examples 1-6 were compounded with a polyvinyl alcohol solution. The content of the matting agent was 3%. A matting agent / polyvinyl alcohol composite film was prepared using the solution casting method. A polyvinyl alcohol film without the application of a matting agent was used as a control group. The glossiness of the matting agents prepared in Examples 1-6 was detected using a 60° glossiness meter, and the matting performance was obtained as shown in Table 1 below:

[0065] Table 1

[0066]

[0067]

[0068] (2) Thermal stability

[0069] The matting agents prepared in Examples 1-6 were compounded with a polyvinyl alcohol solution. The content of the matting agent was 10%. A matting agent / polyvinyl alcohol composite film was prepared using the solution casting method. A polyvinyl alcohol film without the application of a matting agent was used as a control group. The thermal stability of the matting agents prepared in Examples 1-6 was detected respectively, and the obtained results are shown in Table 2 below:

[0070] Table 2

[0071] Toneset (℃) T1max (℃) T2max (℃) Residues at 600℃ (%) Example 1 202.95 278.64 442.62 21.35 Example 2 213.47 295.17 447.21 20.47 Example 3 235.71 309.42 449.68 24.29 Example 4 226.38 301.85 453.25 25.12 Example 5 206.18 275.96 457.14 31.27 Example 6 209.75 283.14 461.38 32.95 Control group 298.61 321.91 439.25 8.10

[0072] Toneset: Temperature at 10% mass loss; T1max and T2max: First and second decomposition peak temperatures of the DTG curve.

[0073] (3) Flame retardancy

[0074] The matting agents prepared in Examples 1-6 were compounded with a polyvinyl alcohol solution. The content of the matting agent was 15%. A matting agent / polyvinyl alcohol composite film was prepared using the solution casting method. A polyvinyl alcohol film without the application of a matting agent was used as a control group. The flame retardancy of the matting agents prepared in Examples 1-6 was detected respectively, and the detection results are shown in Table 3 below:

[0075] Table 3

[0076]

[0077]

[0078] Using a polyvinyl alcohol film without the addition of a matting agent as a control group, 5%, 10%, 15% and 20% of the matting agent were added to the polyvinyl alcohol solution for compounding respectively, and a vertical burning test was carried out on the polyvinyl alcohol film. As Figure 1 shown, the flame retardancy of the polyvinyl alcohol film added with the matting agent was greatly improved.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. Preparation method of phytic acid-melamine / montmorillonite matting agent, characterized in that the steps Including: S1. Dispersing montmorillonite in deionized water to obtain a montmorillonite lamellar dispersion; S2. Dissolving phytic acid and melamine in water, heating and stirring until melamine is dissolved to prepare an ionized melamine phytic acid solution; S3. Mixing the ionized melamine phytic acid solution and the montmorillonite dispersion, reacting to complete the macromolecular self-assembly of phytic acid and melamine with the montmorillonite nanosheets as the core, and forming an aqueous solution of phytic acid-melamine / montmorillonite matting agent.

2. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The montmorillonite is at least one of raw montmorillonite, sodium-based montmorillonite, and calcium-based montmorillonite.

3. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, wherein The ultrasonic treatment of the montmorillonite in water is 0.5 - 2.5 h.

4. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The mass ratio of the total mass of phytic acid and melamine to the mass of montmorillonite is 70 - 100:

1.

5. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The molar ratio of phytic acid to melamine is 4 - 9:

3.

6. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, wherein The heating temperature in step S2 is 95 - 98 °C, and the stirring time is 0.5 - 3.5 h.

7. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The reaction in step S3 includes heating and stirring, and then cooling to room temperature for self-assembly reaction.

8. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The heating temperature is 50 - 115 °C, and the stirring time is 0.5 - 3 h; the self-assembly reaction time is 1 - 24 h.

9. The preparation method of the phytic acid-melamine / montmorillonite matting agent according to claim 1, characterized in that, The method further includes drying the aqueous solution of phytic acid-melamine / montmorillonite matting agent to obtain a solid phytic acid-melamine / montmorillonite matting agent.

10. Application of the matting agent prepared by the preparation method of the phytic acid-melamine / montmorillonite matting agent according to any one of claims 1 - 9 in coatings, plastics, and textiles.

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