A low-viscosity, high-solid-content magnesium hydroxide suspension and a method for preparing the same

Abstract

This invention discloses a low-viscosity, high-solids-content magnesium hydroxide suspension and its preparation method, comprising the following components by mass: 40-60 parts water, 40-60 parts magnesium hydroxide, 0.1-4 parts dispersant, and 0.01-2 parts stabilizer; wherein the viscosity of the magnesium hydroxide suspension is <100 cp; and the particle size D of the magnesium hydroxide is... 50 The particle size is 1~3μm. This invention successfully prepared a low-viscosity, high-solids-content magnesium hydroxide suspension that is stable for a long time and does not exhibit gelation by adding appropriate amounts of dispersants and stabilizers and adjusting the particle size of magnesium hydroxide particles, combined with high-speed stirring and ball milling processes. This not only improves processing efficiency and product performance, but also demonstrates significant economic benefits in transportation and storage.

Description

Technical Field

[0001] This invention relates to the field of powder stabilization and suspension technology, and more specifically, to a low-viscosity, high-solids-content magnesium hydroxide suspension and its preparation method. Background Technology

[0002] Magnesium hydroxide, as an important inorganic material, is widely used in polymer composites, coatings, cable flame retardancy, and wastewater treatment due to its excellent flame retardant properties, environmental friendliness, and low cost. However, in practical applications, the high viscosity and low solids content of magnesium hydroxide slurry severely limit its processing performance and transportation economy. This phenomenon stems from the high surface polarity of magnesium hydroxide particles, which makes them prone to strong agglomeration, forming a three-dimensional network structure, thus significantly increasing the viscosity of the system. Simultaneously, during storage and transportation, magnesium hydroxide particles, due to their higher density than the dispersion medium, settle under gravity, eventually forming a hard sediment layer at the bottom of the container, leading to the destruction of slurry homogeneity and a decline in performance.

[0003] Chinese patent application number 2021115954563 discloses a highly stable magnesium hydroxide suspension and its preparation method. The suspension comprises the following components by mass percentage: 40-80 parts water, 15-50 parts magnesium hydroxide, 0.25-2 parts thickener, 0.25-2 parts stabilizer, and 0-1.5 parts dispersant. This technology, by adding a thickener and adjusting the component ratios, produces a highly stable magnesium hydroxide suspension that does not exhibit stratification or gelation after standing for eight weeks. However, the magnesium hydroxide suspension prepared by this method has a high viscosity, which severely limits its effectiveness in industrial applications requiring good flowability. Furthermore, the magnesium hydroxide in this method has a relatively low solids content and a large particle size, failing to simultaneously meet the dual requirements of high solids content and low viscosity, thus restricting the application of magnesium hydroxide in high-end fields.

[0004] Therefore, developing a magnesium hydroxide suspension that can simultaneously achieve low viscosity, high solids content, and good stability has become a technical challenge to be overcome in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a low-viscosity, high-solids-content magnesium hydroxide suspension and its preparation method.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A low-viscosity, high-solids-content magnesium hydroxide suspension comprises the following components in parts by weight: 40-60 parts water, 40-60 parts magnesium hydroxide, 0.1-4 parts dispersant, and 0.01-2 parts stabilizer; wherein the viscosity of the magnesium hydroxide suspension is <100 cp; and the particle size D of the magnesium hydroxide is... 50 The size is 1~3μm.

[0008] Optionally, the magnesium hydroxide suspension is composed of the following components in parts by weight: 40-60 parts water, 50-60 parts magnesium hydroxide, 0.5-4 parts dispersant and 0.01-1.5 parts stabilizer.

[0009] Optionally, the particle size D of the magnesium hydroxide 50 The value is 1~2.5μm.

[0010] Optionally, the dispersant is at least one selected from sodium oleate, polyepoxysuccinic acid, polyaspartic acid, maleic acid-acrylic acid copolymer, polyacrylate, polyvinyl ester, polyacrylamide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, polysorbate, ammonium polyacrylate, sodium polyacrylate, and sodium polyphosphate. Preferably, the dispersant is at least one selected from sodium oleate, polyacrylate, sodium polyacrylate, and sodium polyphosphate.

[0011] Optionally, the stabilizer is at least one selected from sodium pyrophosphate, sodium metaphosphate, hexadecyl dimethyl ammonium bromide, polyethylene glycol, sodium carboxymethyl cellulose, microcrystalline cellulose, polyvinylpyrrolidone, and oleamide. Preferably, the stabilizer is at least one selected from polyethylene glycol, sodium pyrophosphate, and sodium metaphosphate.

[0012] The present invention also discloses a method for preparing a low-viscosity, high-solids-content magnesium hydroxide suspension as described above, comprising the following steps: using at least one of a high-speed disperser and an emulsifier, water, dispersant, magnesium hydroxide particles and stabilizer are mixed and stirred to disperse evenly, and then added to a planetary ball mill for ball milling to disperse the suspension evenly, thereby obtaining the magnesium hydroxide suspension.

[0013] Optionally, the preparation method specifically includes: using at least one of a high-speed disperser and an emulsifier, mixing water and a dispersant and stirring to disperse them evenly, then sequentially adding magnesium hydroxide particles and a stabilizer, mixing and stirring to disperse them evenly.

[0014] Optionally, the ball milling parameters are: the diameter of the grinding balls is 1 to 10 mm; the ball-to-material ratio is (1 to 5): 1; the ball milling time is 10 to 300 min; and the ball milling speed is 400 r / min.

[0015] Optionally, the grinding balls of the ball mill include grinding balls with a diameter of 5 mm and grinding balls with a diameter of 10 mm; the mass ratio of the grinding balls with a diameter of 5 mm to the grinding balls with a diameter of 10 mm is 1:1.

[0016] Optionally, the stirring speed is 1000~2500 r / min, and the total stirring time is 10~60 min.

[0017] Implementing the embodiments of the present invention will have the following beneficial effects: This invention successfully prepared a low-viscosity, high-solids-content magnesium hydroxide suspension that is stable for a long time and does not exhibit gelation by adding appropriate amounts of dispersants and stabilizers, adjusting the particle size of magnesium hydroxide particles, and combining high-speed stirring and ball milling processes. This not only improves processing efficiency and product performance, but also demonstrates significant economic benefits in transportation and storage. Attached Figure Description

[0018] Figure 1 The magnesium hydroxide suspension prepared in Example 1 is stable and does not separate into layers.

[0019] Figure 2 The magnesium hydroxide suspension prepared in Example 1 is stable, non-gelled, and has good fluidity.

[0020] Figure 3 The image shows the particle size distribution of magnesium hydroxide in the magnesium hydroxide suspension prepared in Example 1. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0022] The parts mentioned in the examples and comparative examples are parts by mass.

[0023] Example 1 The low-viscosity, high-solids-content magnesium hydroxide suspension of this embodiment is composed of the following components by weight: 42 parts water, 53.7 parts magnesium hydroxide, 4 parts sodium polyacrylate, and 0.3 parts sodium pyrophosphate; wherein the particle size D of the magnesium hydroxide is... 50 It is 1~1.5μm.

[0024] The method for preparing the low-viscosity, high-solids-content magnesium hydroxide suspension in this embodiment includes the following steps: Weigh the raw materials according to the above-mentioned mass proportions, place water and sodium polyacrylate in a mixing tank, and stir for 3 minutes at 1500 r / min using a high-speed disperser to mix them evenly. Then add magnesium hydroxide granules (particle size D). 50The particle size (1~2.5 μm) of the mixture was stirred for 10 min to ensure homogeneity. Sodium pyrophosphate was then added to the suspension, and the mixture was stirred at 1500 rpm for 10 min to ensure uniform dispersion. The suspension was then added to a ball mill jar containing 5 mm and 10 mm grinding balls at a mass ratio of 1:1 (ball-to-material ratio 1:1), and ball milled at 400 rpm for 3 h to ensure uniform dispersion. The resulting suspension had a viscosity of 50 cp. After standing for 8 weeks, a small amount of sediment appeared at the bottom, which was easily restored to fluidity by gentle shaking.

[0025] Example 2 The only difference between this embodiment and Embodiment 1 is that the ball milling time is 4 hours.

[0026] The viscosity of the suspension obtained in this embodiment is 50 cp. After the suspension is left to stand for 8 weeks, a small amount of sediment appears at the bottom. Slight shaking can restore its fluidity.

[0027] Comparative Example 1 The magnesium hydroxide suspension in this comparative example is composed of the following components by mass: 42 parts water, 57.95 parts magnesium hydroxide, and 0.05 parts sodium polyacrylate; wherein the particle size D of the magnesium hydroxide is... 50 The thickness is 1.5~2.5μm.

[0028] The preparation method of the magnesium hydroxide suspension in this comparative example includes the following steps: weigh the raw materials according to the above-mentioned mass proportions, add water and sodium polyacrylate to a mixing tank, use a high-speed disperser to stir at 1500 r / min for 3 min, mix the two evenly, and then add magnesium hydroxide particles (particle size D). 50 (The particle size is 1~2.5μm). Stir the mixed slurry for 10 minutes to ensure uniform mixing. The resulting suspension has a viscosity of 1500cp. After standing for half a day, gelation occurs in the suspension. This is due to the low amount of dispersant added, the absence of stabilizer, and the large particle size.

[0029] Comparative Example 2 The magnesium hydroxide suspension in this comparative example is composed of the following components in parts by mass: 42 parts water, 54 parts magnesium hydroxide, and 4 parts sodium polyacrylate; wherein the particle size D of the magnesium hydroxide is... 50 The thickness is 1.5~2.5μm.

[0030] The preparation method of the magnesium hydroxide suspension in this comparative example includes the following steps: weigh the raw materials according to the above-mentioned mass proportions, add water and sodium polyacrylate to a mixing tank, and stir using a high-speed disperser at 1500 r / min for 3 min to mix them evenly. Then add magnesium hydroxide particles (particle size D). 50(The particle size is 1~2.5μm). Stir the mixed slurry for 10 minutes to ensure uniform mixing. The viscosity of the resulting suspension is 55.8cp. After the suspension has been left to stand for 8 weeks, a large amount of sediment has appeared at the bottom, which is caused by the lack of stabilizer and the large particle size.

[0031] Comparative Example 3 The magnesium hydroxide suspension in this comparative example is composed of the following components by mass: 42 parts water, 51 parts magnesium hydroxide, 4 parts sodium polyacrylate, and 3 parts sodium pyrophosphate; wherein the particle size D of the magnesium hydroxide is... 50 The thickness is 1.5~2.5μm.

[0032] The preparation method of the magnesium hydroxide suspension in this comparative example includes the following steps: weigh the raw materials according to the above-mentioned mass proportions, add water and sodium polyacrylate to a mixing tank, and stir using a high-speed disperser at 1500 r / min for 3 min to mix them evenly. Then add magnesium hydroxide particles (particle size D). 50 The particle size was 1~2.5μm. The mixed slurry was stirred for 10 minutes to ensure uniform mixing. Sodium pyrophosphate was then added to the suspension, and the mixture was stirred at 1500 rpm for 10 minutes to ensure uniform dispersion. The resulting suspension had a viscosity of 150 cp. After standing for one day, gelation occurred, which was attributed to excessive stabilizer addition and large particle size.

[0033] Comparative Example 4 The magnesium hydroxide suspension in this comparative example is composed of the following components by mass: 42 parts water, 53.7 parts magnesium hydroxide, 4 parts sodium polyacrylate, and 0.3 parts sodium pyrophosphate; wherein the particle size D of the magnesium hydroxide is... 50 The thickness is 1.5~2.5μm.

[0034] The preparation method of the magnesium hydroxide suspension in this comparative example includes the following steps: weigh the raw materials according to the above-mentioned mass proportions, add water and sodium polyacrylate to a mixing tank, and stir using a high-speed disperser at 1500 r / min for 3 min to mix them evenly. Then add magnesium hydroxide particles (particle size D). 50 The slurry (with a particle size of 1–2.5 μm) was stirred for 10 minutes to ensure uniform mixing. Sodium pyrophosphate was then added to the suspension, and the mixture was stirred at 1500 rpm for 10 minutes to ensure uniform dispersion. The resulting suspension had a viscosity of 57.1 cp. After standing for 8 weeks, a moderate amount of sediment appeared at the bottom, which was attributed to the relatively large particle size of magnesium hydroxide.

[0035] Example 3 The only difference between this embodiment and Embodiment 1 is that the ball milling time is 1 hour.

[0036] The resulting suspension had a viscosity of 50 cp. After standing for 8 weeks, a small amount of sediment appeared at the bottom, which could be partially restored to fluidity by gentle shaking. Example 4 The difference between this embodiment and Embodiment 1 is that the ball milling time is 2 hours.

[0037] The resulting suspension had a viscosity of 50 cp. After standing for 8 weeks, a small amount of sediment appeared at the bottom, which could be partially restored to fluidity by gentle shaking.

[0038] Example 5 The difference between this embodiment and Embodiment 1 is that the ball milling time is 5 hours.

[0039] The resulting suspension had a viscosity of 50 cp. After standing for 8 weeks, a small amount of sediment appeared at the bottom, which could be partially restored to fluidity by gentle shaking.

[0040] Comparative Example 5 The magnesium hydroxide suspension in this comparative example is composed of the following components by mass: 42 parts water, 53.7 parts magnesium hydroxide, 4 parts sodium polyacrylate, and 0.3 parts sodium pyrophosphate; wherein the particle size D of the magnesium hydroxide is... 50 The size ranges from 0.5 to 1 μm.

[0041] The preparation method of the magnesium hydroxide suspension in this comparative example includes the following steps: weigh the raw materials according to the above-mentioned mass proportions, add water and sodium polyacrylate to a mixing tank, and stir using a high-speed disperser at 1500 r / min for 3 min to mix them evenly. Then add magnesium hydroxide particles (particle size D). 50 The magnesium hydroxide particles (1~2.5 μm) were stirred for 15 min to ensure uniform mixing. Sodium pyrophosphate was then added to the suspension, and the mixture was stirred at 1500 rpm for 10 min to ensure uniform dispersion. The suspension was then added to a ball mill jar containing 5 mm and 10 mm grinding balls at a mass ratio of 1:1 (ball-to-material ratio 1:1), and ball milled at 400 rpm for 6 h to ensure uniform dispersion. The resulting suspension had a viscosity of 100 cp. After standing for one day, gelation occurred, which is attributed to the small particle size of magnesium hydroxide, preventing the additive from maintaining its stable state.

[0042] In summary, by means of the above-mentioned technical solution of the present invention, the present invention prepares a low-viscosity, high-solids-content, and high-stability magnesium hydroxide slurry by adding appropriate amounts of dispersant and stabilizer and by adjusting the particle size of magnesium hydroxide particles. The slurry has low viscosity (less than 100 cp) and good fluidity; it also has good stability. If a small amount of sediment occurs after standing for 8 weeks, it can be resuspended by slight stirring.

[0043] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A low-viscosity, high-solids-content magnesium hydroxide suspension, characterized in that, It is composed of the following components in parts by weight: 40-60 parts water, 40-60 parts magnesium hydroxide, 0.1-4 parts dispersant and 0.01-2 parts stabilizer; Wherein, the viscosity of the magnesium hydroxide suspension is <100 cp; the particle size D of the magnesium hydroxide is... 50 The size is 1~3μm.

2. The low-viscosity, high-solids-content magnesium hydroxide suspension according to claim 1, characterized in that, The magnesium hydroxide suspension is composed of the following components in parts by weight: 40-60 parts water, 50-60 parts magnesium hydroxide, 0.5-4 parts dispersant and 0.01-1.5 parts stabilizer.

3. The low-viscosity, high-solids-content magnesium hydroxide suspension according to claim 1, characterized in that, The particle size D of the magnesium hydroxide 50 The value is 1~2.5μm.

4. The low-viscosity, high-solids-content magnesium hydroxide suspension according to claim 1, characterized in that, The dispersant is at least one selected from sodium oleate, polyepoxysuccinic acid, polyaspartic acid, maleic acid-acrylic acid copolymer, polyacrylate, polyvinyl ester, polyacrylamide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, polysorbate, ammonium polyacrylate, sodium polyacrylate, and sodium polyphosphate.

5. The low-viscosity, high-solids-content magnesium hydroxide suspension according to claim 1, characterized in that, The stabilizer is at least one of sodium pyrophosphate, sodium metaphosphate, hexadecyl dimethyl ammonium bromide, polyethylene glycol, sodium carboxymethyl cellulose, microcrystalline cellulose, polyvinylpyrrolidone, and oleamide.

6. A method for preparing a low-viscosity, high-solids-content magnesium hydroxide suspension as described in any one of claims 1-5, characterized in that, Includes the following steps: Using at least one of a high-speed disperser and an emulsifier, water, dispersant, magnesium hydroxide particles and stabilizer are mixed and stirred until uniformly dispersed. Then, the mixture is added to a planetary ball mill for ball milling to ensure uniform dispersion of the suspension, thereby obtaining the magnesium hydroxide suspension.

7. The preparation method according to claim 6, characterized in that, The ball milling parameters are as follows: the diameter of the grinding balls is 1 to 10 mm; the ball-to-material ratio is (1 to 5): 1; the ball milling time is 10 to 300 min; and the ball milling speed is 400 r / min.

8. The preparation method according to claim 7, characterized in that, The grinding balls of the ball mill include grinding balls with a diameter of 5 mm and grinding balls with a diameter of 10 mm; the mass ratio of the grinding balls with a diameter of 5 mm to the grinding balls with a diameter of 10 mm is 1:

1.

9. The preparation method according to claim 6, characterized in that, The stirring speed is 1000~2500 r / min, and the stirring time is 10~60 min.

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