CN110980780B - Preparation method of flaky magnesium hydroxide flame retardant - Google Patents
Preparation method of flaky magnesium hydroxide flame retardant Download PDFInfo
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- CN110980780B CN110980780B CN201911331567.6A CN201911331567A CN110980780B CN 110980780 B CN110980780 B CN 110980780B CN 201911331567 A CN201911331567 A CN 201911331567A CN 110980780 B CN110980780 B CN 110980780B
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/14—Magnesium hydroxide
- C01F5/22—Magnesium hydroxide from magnesium compounds with alkali hydroxides or alkaline- earth oxides or hydroxides
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Abstract
The invention provides a preparation method of a flaky magnesium hydroxide flame retardant, which comprises the following steps: putting a magnesium chloride solution into a reaction kettle, adding an amphoteric triblock copolymer crystal form directing agent, uniformly stirring, heating to 30-70 ℃ for the first time, dropwise adding sodium hydroxide into the reaction kettle at a constant speed in a stirring state, and keeping the temperature of 50-65 ℃ after dropwise adding is finished, stirring and reacting for 1 h; stopping stirring, heating to 70-90 ℃, carrying out normal-pressure hydrothermal aging reaction for 12-36h, and carrying out filter pressing, washing, drying and crushing to obtain the flaky magnesium hydroxide flame retardant; the crystal form directing agent is an amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide. In the invention, the sheet magnesium hydroxide flame retardant is prepared by one-step reaction at normal pressure and medium temperature by using the amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide as a crystallization guiding agent without replacing a reaction container.
Description
Technical Field
The invention relates to the technical field of chemical materials, and particularly belongs to a preparation method of a flaky magnesium hydroxide flame retardant.
Background
Magnesium hydroxide is a novel filling type flame retardant, releases combined water in the process of thermal decomposition, absorbs a large amount of latent heat, reduces the surface temperature of the filled material in flame, has the effects of inhibiting the decomposition of polymers and cooling the generated combustible gas, optimizes the fire resistance of the synthetic material, and has the effect of inhibiting smoke by the water vapor released by decomposition. Therefore, the magnesium hydroxide is a high-quality flame retardant with triple functions of smoke suppression, filling and flame retardance. In conclusion, the magnesium hydroxide has the characteristics of no toxicity, no harm, acid resistance and thermodynamic stability, has the advantages of heat absorption and smoke suppression functions when a polymer is combusted, and belongs to an environment-friendly flame retardant. The characteristics and advantages are derived from the crystal morphology, size and dispersity of the magnesium hydroxide crystal, and are the physical and chemical properties of the magnesium hydroxide crystal; the magnesium hydroxide crystal with a sheet structure has filling and halogen-free flame retardant functions in thermoplastic polymers and fiber materials due to special structure, mechanical property and dispersity, and can improve the combustion initial temperature of the polymer materials and enhance the thermal stability of the polymer materials. Therefore, the flaky magnesium hydroxide crystal flame retardant material becomes one of the hot spots of research in the field of flame retardants.
Chinese patent document CN102205980B discloses a preparation method of a monodisperse flaky magnesium hydroxide flame retardant, which comprises the following steps:
(1) preparing a soluble magnesium salt solution, wherein the concentration of magnesium ions is between 4mol/L and 0.5 mol/L;
(2) preparing an alkali solution, wherein the concentration of hydroxide ions is between 8 and 0.5 mol/L;
(3) under the conditions of normal pressure, reaction temperature of 25-60 ℃, stirring speed of 1500-;
(4) transferring the slurry into a high-pressure reaction kettle for hydrothermal reaction, wherein the water temperature is 100-;
(5) filtering, washing, and drying the washed product at the temperature of 100-160 ℃ for 4-6h to obtain the magnesium hydroxide flame retardant with the shape of hexagonal sheet or disk and the particle size of 200-500 nm.
The preparation process is divided into two steps of operation, wherein one step is carried out at normal pressure and the reaction temperature is 25-60 ℃; then the slurry is transferred to a high-pressure reaction kettle for hydrothermal reaction, and the water temperature is 100-200 ℃.
Chinese patent document CN106673027A discloses a preparation and synthesis method of hexagonal flaky magnesium hydroxide flame retardant, which comprises the following steps:
adding a magnesium salt solution and a crystallization guiding agent into a reaction container, uniformly stirring at 30-50 ℃, dropwise adding an inorganic alkali solution into the reaction container at a constant speed under the temperature condition, after the reaction is completed, carrying out ultrasonic oscillation on reaction slurry for 20-30min, transferring the reaction slurry into a high-pressure reaction kettle, adding anhydrous ethanol, carrying out hydrothermal reaction at the temperature of 150 ℃ and 220 ℃ for 12-72h, and finally carrying out filter pressing, washing and drying to obtain a magnesium hydroxide product.
The preparation process is divided into two steps of operation, and the reaction temperature of one step is 30-50 ℃; after ultrasonic oscillation, the mixture is transferred into a high-pressure reaction kettle for carrying out hydrothermal reaction at the temperature of 150-220 ℃.
The processes for preparing the magnesium hydroxide flame retardant are all carried out in a high-pressure reaction kettle, and the requirements on reaction conditions are high.
Disclosure of Invention
The preparation method of the flaky magnesium hydroxide flame retardant provided by the invention is used for achieving the purposes of reducing the process reaction conditions and adjusting the morphology of magnesium hydroxide in the preparation process.
A preparation method of a flaky magnesium hydroxide flame retardant is characterized by comprising the following steps:
putting the weighed magnesium chloride solution into a reaction kettle, adding an amphiphilic triblock copolymer crystal form directing agent, uniformly stirring, heating to 30-70 ℃ for the first time, dropwise adding sodium hydroxide into the reaction kettle at a constant speed in a stirring state, and keeping the temperature at 50-65 ℃ after dropwise adding is finished, stirring and reacting for 1 h; stopping stirring, heating to 70-90 ℃, carrying out normal-pressure hydrothermal aging reaction for 12-36h, and carrying out filter pressing, washing, drying and crushing to obtain the flaky magnesium hydroxide flame retardant; wherein the molar ratio of the magnesium chloride to the sodium hydroxide is nMagnesium chloride：nSodium hydroxide1: 2-4; the crystal form directing agent is an amphoteric triblock copolymer (EO) of polyethylene oxide and polypropylene oxidenPOmEOn)。
Preferably, the molar ratio of the magnesium chloride to the sodium hydroxide is nMagnesium chloride：nSodium hydroxide＝1:2.5。
Preferably, the magnesium chloride solution is obtained by refining underground brine after solar salt drying, or is obtained by dissolving solid magnesium chloride, and the concentration of the magnesium chloride in a reaction system is 0.5-3 mol/L; the concentration of the sodium hydroxide is 1-5 mol/L.
Preferably, the stirring speed of the sodium hydroxide during adding is 150-500 r/min.
Preferably, the concentration of magnesium chloride in the reaction system is 0.75 mol/L; the concentration of sodium hydroxide was 2.35 mol/L.
Preferably, the amphiphilic triblock copolymer is a triblock copolymer of polyethylene oxide and polypropylene oxide (EO)nPOmEOn) Wherein m isPolypropylene oxide70, the ratio of polyethylene oxide units to polypropylene oxide units nPolyethylene oxide：mPolypropylene oxide0.1-2.0; the concentration in the reaction system is 0.5-5.0 g/L.
Preferably, the amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide is EO106PO70EO106The concentration in the reaction system was 2.0 g/L.
Preferably, the first temperature rise temperature is 35 ℃; the hydrothermal aging reaction temperature is 80 ℃, and the time is 24 h.
The invention has the beneficial effects that:
in the invention, the amphoteric triblock copolymer (EO) of polyethylene oxide and polypropylene oxide is adoptednPOmEOn) The flaky magnesium hydroxide flame retardant is prepared by one-step reaction of a crystallization guiding agent at normal pressure and medium temperature, and a reaction container does not need to be replaced. By utilizing the oxygen affinity characteristic of magnesium ions, in the process of generating magnesium hydroxide, adding an amphoteric triblock copolymer as a crystal form directing agent, regulating the nucleation of magnesium hydroxide, controlling the growth of the crystal form, and modifying the surface of a magnesium hydroxide crystal to prepare the magnesium hydroxide crystal in a sheet structure.
The method has the advantages of convenient raw material source, low price, simple operation steps, short process flow, low energy consumption, less input equipment, avoidance of the use of a high-pressure reaction kettle, stable flaky shape of the prepared magnesium hydroxide, uniform particle size distribution and the like, and has good market application prospect.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) image of the magnesium hydroxide prepared in example 5 of the present invention as dispersed flaky crystals.
FIG. 2 is an X-ray diffraction (XRD) pattern of magnesium hydroxide prepared in example 2 of the present invention, which is substantially identical to the standard pattern JCPDS44-1482 of magnesium hydroxide.
FIG. 3 is a graph showing the distribution of the particle size distribution (in micrometers on the abscissa) of magnesium hydroxide prepared in example 5 of the present invention, the particle size distribution being uniform, and D50 being 1.88 um.
FIG. 4 is a Scanning Electron Microscope (SEM) image of magnesium hydroxide in the prior art, which is irregular in shape and has agglomeration.
Detailed Description
The present invention will be further described with reference to specific examples, wherein the experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.
Example 1
A25L reactor was charged with 7.5L of a 1.5mol/L aqueous magnesium chloride solution, 22 g of an amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide (EO)20PO70EO20) Heating to 60 deg.c; adjusting the stirring speed to 400 r/m, adding 8 liters of sodium hydroxide solution with the concentration of 4mol/L by a constant flow pump, controlling the flow rate to be about 0.2L/m, and continuing to perform heat preservation reaction at 60 ℃ for 1h after the addition is finished; heating to 90 ℃, stopping stirring and ageing for 12h, cooling to room temperature, then filtering, discharging, filtering by using a positive pressure filter, washing a filter cake for 3-5 times by using distilled water, taking the detection of no chloride ion in the filtrate as an end point, and placing the precipitate in a 105 ℃ oven for drying and crushing to obtain a magnesium hydroxide flame retardant product (marked as MH-1).
Example 2
To a 25 liter reaction vessel, 10 liters of a 1.5mol/L magnesium chloride aqueous solution was added, and 9 g of an amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide (EO) was added45PO70EO45) Heating to 30 ℃; adjusting the stirring speed to 350 r/m, adding 8 liters of sodium hydroxide solution with the concentration of 4mol/L by a constant flow pump, controlling the flow rate to be about 0.2L/m, and continuing to perform heat preservation reaction at 50 ℃ for 1h after the addition is finished; heating to 70 deg.C, stopping stirring and aging for 30 hr, cooling to room temperature, filtering, discharging, filtering with positive pressure filter, filtering with distilled water to obtain filter cakeWashing for 3-5 times, and drying and pulverizing the precipitate in a 105 deg.C oven to obtain magnesium hydroxide flame retardant (marked as MH-2).
Example 3
A25 liter reaction vessel was charged with 7 liters of a 4mol/L magnesium chloride aqueous solution, and 50 g of an amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide (EO)60PO70EO60) Heating to 50 deg.C; adjusting the stirring speed to 150 r/m, adding 5 liters of sodium hydroxide solution with the concentration of 12mol/L by a constant flow pump, controlling the flow rate to be about 0.2 liter/m, and continuing to perform heat preservation reaction at 55 ℃ for 1h after the addition is finished; heating to 80 ℃, stopping stirring and ageing for 18h, cooling to room temperature, then filtering, discharging, filtering by using a positive pressure filter, washing a filter cake for 3-5 times by using distilled water, taking the detection of no chloride ion in the filtrate as an end point, and placing the precipitate in a 105 ℃ oven for drying and crushing to obtain a magnesium hydroxide flame retardant product (marked as MH-3).
Example 4
A25 liter reaction vessel was charged with 4 liters of a 3mol/L magnesium chloride aqueous solution, and 35 g of an amphiphilic triblock copolymer of polyethylene oxide and polypropylene oxide (EO)80PO70EO80) Heating to 70 deg.c; adjusting the stirring speed to 450 r/m, adding 6 liters of 6mol/L sodium hydroxide solution by a constant flow pump, controlling the flow rate to be about 0.2 liter/m, and continuing to perform heat preservation reaction at 60 ℃ for 1h after the addition is finished; heating to 75 ℃, stopping stirring and ageing for 36h, cooling to room temperature, then filtering, discharging, filtering by using a positive pressure filter, washing a filter cake for 3-5 times by using distilled water, taking the detection of no chloride ion in the filtrate as an end point, and placing the precipitate in a drying oven at 105 ℃ for drying and crushing to obtain a magnesium hydroxide flame retardant product (marked as MH-4).
Example 5
A25 liter reaction vessel was charged with 10 liters of a 1.5mol/L magnesium chloride aqueous solution, 2.5 liters of distilled water, 40 g of an amphoteric triblock copolymer of polyethylene oxide and polypropylene oxide (EO)106PO70EO106) Heating to 35 ℃; the stirring speed is adjusted to 500r/m, and then 7.5 liters of solution with the concentration ofControlling the flow rate of 4mol/L sodium hydroxide solution to be about 0.2 liter/minute, and continuing to perform heat preservation reaction at 60 ℃ for 1 hour after the addition is finished; heating to 80 ℃, stopping stirring and ageing for 24 hours, cooling to room temperature, then filtering, discharging, filtering by using a positive pressure filter, washing a filter cake for 3-5 times by using distilled water, taking the detection of no chloride ion in the filtrate as an end point, and placing the precipitate in a 105 ℃ oven for drying and crushing to obtain a magnesium hydroxide flame retardant product (marked as MH-5).
The products obtained in examples 1 to 5 were subjected to the performance test, and the results of the test items are shown in Table 1 below
TABLE 1 magnesium hydroxide flame retardant product Properties
The performance tests in Table 1 show that the magnesium hydroxide flame retardant product prepared by the invention meets the MC-2-15 index requirements in the chemical industry standard HG/T4531-2013.
Claims (7)
1. A preparation method of a flaky magnesium hydroxide flame retardant is characterized by comprising the following steps:
putting the weighed magnesium chloride solution into a reaction kettle, adding an amphiphilic triblock copolymer crystal form directing agent, uniformly stirring, heating to 30-70 ℃ for the first time, dropwise adding sodium hydroxide into the reaction kettle at a constant speed in a stirring state, and keeping the temperature at 50-65 ℃ after dropwise adding is finished, stirring and reacting for 1 h; stopping stirring, heating to 70-90 ℃, carrying out normal-pressure hydrothermal aging reaction for 12-36h, and carrying out filter pressing, washing, drying and crushing to obtain the flaky magnesium hydroxide flame retardant; wherein the molar ratio of the magnesium chloride to the sodium hydroxide is nMagnesium chloride：nSodium hydroxide1: 2-4; the crystal form directing agent is an amphoteric triblock copolymer EO of polyethylene oxide and polypropylene oxidenPOmEOn(ii) a The amphiphilic triblockCopolymer EOnPOmEOnWherein m isPolypropylene oxide=70, ratio of polyethylene oxide units to polypropylene oxide units nPolyethylene oxide：mPolypropylene oxide= 0.1-2.0; the concentration in the reaction system is 0.5-5.0 g/L.
2. The method for preparing the flaky magnesium hydroxide flame retardant according to claim 1, wherein the molar ratio of magnesium chloride to sodium hydroxide is n-magnesium chloride: n sodium hydroxide =1: 2.5.
3. The preparation method of the flaky magnesium hydroxide flame retardant according to claim 1, wherein the magnesium chloride solution is obtained by refining underground brine after solar salting, or is obtained by dissolving solid magnesium chloride, and the concentration of the magnesium chloride in a reaction system is 0.5-3 mol/L; the concentration of the sodium hydroxide is 1-5 mol/L.
4. The preparation method of the flaky magnesium hydroxide flame retardant according to claim 1, wherein the stirring speed during the addition of the sodium hydroxide is 150 to 500 r/min.
5. The method for preparing a flaky magnesium hydroxide flame retardant according to claim 1, wherein the concentration of magnesium chloride in the reaction system is 0.75 mol/L; the concentration of sodium hydroxide was 2.35 mol/L.
6. The method for preparing a sheet-like magnesium hydroxide flame retardant according to claim 1, wherein the amphiphilic triblock copolymer is EO106PO70EO106The concentration in the reaction system was 2.0 g/L.
7. The method for preparing a flaky magnesium hydroxide flame retardant according to claim 1, wherein the first temperature rise is 35 ℃; the hydrothermal aging reaction temperature is 80 ℃, and the time is 24 h.
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| CN1359853A (en) * | 2000-12-19 | 2002-07-24 | 中国科学技术大学 | Acidular or flaky nano magnesium hydroxide and its preparing process |
| CN101700899A (en) * | 2009-10-28 | 2010-05-05 | 钟辉 | Technology for producing and preparing high-purity lamellar magnesium hydroxide |
| CN104495883A (en) * | 2014-12-02 | 2015-04-08 | 中国科学院青海盐湖研究所 | Preparation method of magnesium hydrate with high-concentration slurry |
| CN106673027A (en) * | 2016-12-30 | 2017-05-17 | 安徽壹石通材料科技股份有限公司 | Preparation and synthesis method of hexagonal flaky magnesium hydroxide fire retardant |
| CN106995215A (en) * | 2017-04-18 | 2017-08-01 | 太原理工大学 | A kind of mesoporous orderly Mg-Al composite oxide material of macropore and preparation method thereof |
| CN108975360A (en) * | 2018-07-20 | 2018-12-11 | 大连理工大学 | A kind of preparation method, device and the application of spherical shape magnesia |
| CN109133126A (en) * | 2018-08-23 | 2019-01-04 | 中国科学院青海盐湖研究所 | A kind of magnesium hydroxide products and preparation method thereof |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1359853A (en) * | 2000-12-19 | 2002-07-24 | 中国科学技术大学 | Acidular or flaky nano magnesium hydroxide and its preparing process |
| CN101700899A (en) * | 2009-10-28 | 2010-05-05 | 钟辉 | Technology for producing and preparing high-purity lamellar magnesium hydroxide |
| CN104495883A (en) * | 2014-12-02 | 2015-04-08 | 中国科学院青海盐湖研究所 | Preparation method of magnesium hydrate with high-concentration slurry |
| CN106673027A (en) * | 2016-12-30 | 2017-05-17 | 安徽壹石通材料科技股份有限公司 | Preparation and synthesis method of hexagonal flaky magnesium hydroxide fire retardant |
| CN106995215A (en) * | 2017-04-18 | 2017-08-01 | 太原理工大学 | A kind of mesoporous orderly Mg-Al composite oxide material of macropore and preparation method thereof |
| CN108975360A (en) * | 2018-07-20 | 2018-12-11 | 大连理工大学 | A kind of preparation method, device and the application of spherical shape magnesia |
| CN109133126A (en) * | 2018-08-23 | 2019-01-04 | 中国科学院青海盐湖研究所 | A kind of magnesium hydroxide products and preparation method thereof |
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