CN114292532A - Magnesium hydroxide ultra-fining and surface modification method and application thereof - Google Patents
Magnesium hydroxide ultra-fining and surface modification method and application thereof Download PDFInfo
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- CN114292532A CN114292532A CN202210011604.0A CN202210011604A CN114292532A CN 114292532 A CN114292532 A CN 114292532A CN 202210011604 A CN202210011604 A CN 202210011604A CN 114292532 A CN114292532 A CN 114292532A
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Abstract
The invention discloses a method for superfine grinding and surface modification of magnesium hydroxide and application thereof, wherein a vertical mill/jet mill twice grinding and twice mechanochemical reaction modification integrated process is used for preparing a magnesium hydroxide flame retardant, and the method comprises the following steps: selecting brucite powder with the particle size of 10-50 mm, a surface modifier and a solvent, continuously adding the brucite powder, the surface modifier and the solvent into a vertical mill, and carrying out primary superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃; adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment; collecting, drying and packaging the treated magnesium hydroxide powder. Improves the compatibility with the high polymer material, obviously improves the mechanical property, the processing fluidity, the flame retardant property and the like of the high polymer composite material, and can be widely applied to the industrial production process.
Description
Technical Field
The invention relates to the technical field of magnesium hydroxide flame retardants, in particular to a method for superfine and surface modification of magnesium hydroxide and application thereof.
Background
The development trend of the flame retardant in the world of the 21 st century is moving towards environmental protection, low toxicity, low smoke, high efficiency and multiple functions, Europe has started to limit the sale of halogen-containing flame retardants, Japan prohibits the use of flame retardants which generate acid gases when cables are burned, and the United states has established regulations for using low-halogen cable coating layers. With the rapid development of Chinese economic construction, modern equipment such as many high-rise buildings, subways, tunnels, nuclear power stations, ships and the like are required to adopt low-smoke halogen-free flame-retardant wires and cables, and the requirements on the safety performance and the environmental protection performance of the flame retardant are higher and higher.
The flame retardant property of magnesium hydroxide completely meets the requirement of flame retardant for development to environment protection, and belongs to an inorganic non-halogen flame retardant which is harmless to human health and environment protection.
The surface of the magnesium hydroxide flame retardant is hydrophilic and oleophobic, the magnesium hydroxide powder without surface treatment is filled in a polymer material, and is difficult to uniformly disperse in an organic high polymer, and the mechanical property, the processing property and the like of the polymer material are seriously deteriorated, so the magnesium hydroxide needs to be subjected to surface modification treatment to improve the compatibility of the magnesium hydroxide and the polymer and reduce the influence of the magnesium hydroxide on the processing property and the mechanical property of a polymer product.
The dry mechanochemical modification is that the surface activity of particles is enhanced by crushing, grinding, rubbing and other methods, so that the surface of powder with strong activity reacts and is attached to a surface modifier, thereby achieving the purpose of surface modification. The method has the advantages of simple process, convenient operation, high efficiency, high yield, energy saving, environmental protection, no pollution and the like, has wide development prospect, and provides a magnesium hydroxide superfine and surface modification method and application thereof for solving the problems.
Disclosure of Invention
The invention aims to provide a magnesium hydroxide ultra-fining and surface modification method and application thereof, so as to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a method for superfine grinding and surface modification of magnesium hydroxide is to prepare a magnesium hydroxide flame retardant by an integrated process of two times of grinding and two times of mechanochemical reaction modification through a vertical mill/jet mill, and comprises the following steps:
s1, selecting brucite powder with the particle size of 10-50 mm, a surface modifier and a solvent, continuously adding the brucite powder, the surface modifier and the solvent into a vertical mill, and performing first superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃;
s2, adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment;
and S3, collecting, drying and packaging the treated magnesium hydroxide powder.
In a preferred embodiment, in step S1, the particle size of the modified magnesium hydroxide fine powder after the first integrated ultrafine grinding and mechanochemical modification treatment is 800-1500 meshes; in step S2, the particle size of the modified magnesium hydroxide fine powder after the second integrated treatment of ultrafine grinding and mechanochemical modification is 2500-8000 meshes.
In a preferred embodiment, in step S1, the surface modifier is one or more of stearic acid, organic carboxylate, silane coupling agent RS iX3, titanate coupling agent and phosphate coupling agent, and the solvent is one or more of organic auxiliaries such as absolute ethyl alcohol, acetone and toluene.
In a preferred embodiment, the silane modifier is RS iX3, wherein R is amino, mercapto, vinyl, epoxy, cyano, or methacryloxy, and X is halogen, alkoxy, or acyloxy.
In a preferred embodiment, in step S1, the amount of the surface modifier is 0.5-5% by mass of the brucite powder, and the amount of the solvent is 0.5-2 times by mass of the surface modifier.
The application of the magnesium hydroxide superfine and surface modification method is applied to low-smoke halogen-free cable materials, and is characterized in that: the low-smoke halogen-free cable material comprises the following raw materials in parts by weight: 88 parts of base resin, 12 parts of compatilizer, 165 parts of halogen-free flame retardant, 2 parts of coupling agent, 3 parts of lubricant and 1 part of antioxidant.
In a preferred embodiment, the halogen-free flame retardant is magnesium hydroxide modified fine powder, the compatilizer is maleic anhydride grafted polyethylene, the lubricant is one or more of polyethylene wax, silicone powder and methyl silicone oil, and the antioxidant is a mixture of pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and distearyl thiodipropionate in a mass ratio of 3: 4.
The invention has the beneficial effects that:
1. the cable material prepared by carrying out superfine grinding and mechanochemical modification integrated treatment on magnesium hydroxide is more excellent in performance compared with the cable material prepared by obtaining the magnesium hydroxide flame retardant after common grinding treatment, has finer surface particle size distribution, is more smooth and fine, has more excellent elongation and melt index performance, and has popularization and use values;
2. the process for preparing the magnesium hydroxide flame retardant by integrating the superfine powder and the surface modification has the advantages of simplicity, convenient operation, high efficiency, high yield, low energy consumption, environmental protection and no pollution, and can be widely applied to the industrial production process; the modified superfine magnesium hydroxide prepared by the invention improves the compatibility with a high polymer material, and obviously improves the mechanical property, the processing fluidity, the flame retardant property and the like of a high polymer composite material.
Drawings
FIG. 1 is a diagram showing the extruded state of a cable prepared from magnesium hydroxide in a control according to the present invention.
FIG. 2 is a diagram showing an extruded state of a cable prepared from magnesium hydroxide in example 1 of the present invention.
FIG. 3 is a diagram showing an extruded state of a cable prepared from magnesium hydroxide in example 2 of the present invention.
FIG. 4 is a diagram showing an extruded state of a cable prepared from magnesium hydroxide in example 3 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1: the invention provides a method for superfine grinding and surface modification of magnesium hydroxide, which prepares a magnesium hydroxide flame retardant by an integrated process of twice grinding and twice mechanochemical reaction modification by a vertical mill/jet mill, and comprises the following steps:
s1, selecting brucite powder with the particle size of 10-50 mm, 1.5% of stearic acid surface modifier and absolute ethyl alcohol, continuously adding the brucite powder, the stearic acid surface modifier and the absolute ethyl alcohol into a vertical mill, and performing first superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃ to prepare 800-1500-mesh magnesium hydroxide modified fine powder;
s2, adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment to prepare 2500-8000-mesh magnesium hydroxide modified fine powder;
and S3, collecting, drying and packaging the treated magnesium hydroxide powder.
Example 2: the invention provides a method for superfine grinding and surface modification of magnesium hydroxide, which prepares a magnesium hydroxide flame retardant by an integrated process of twice grinding and twice mechanochemical reaction modification by a vertical mill/jet mill, and comprises the following steps:
s1, selecting brucite powder with the particle size of 10-50 mm, 1.0% of stearic acid, 1.0% of titanate surface modifier and acetone, continuously adding into a vertical mill, and performing first superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃ to prepare 800-1500-mesh magnesium hydroxide modified fine powder;
s2, adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment to prepare 2500-8000-mesh magnesium hydroxide modified fine powder;
and S3, collecting, drying and packaging the treated magnesium hydroxide powder.
Example 3: the invention provides a method for superfine grinding and surface modification of magnesium hydroxide, which prepares a magnesium hydroxide flame retardant by an integrated process of twice grinding and twice mechanochemical reaction modification by a vertical mill/jet mill, and comprises the following steps:
s1, selecting brucite powder with the particle size of 10-50 mm, 1.5 percent of vinyl tri (beta-methoxyethoxy) silane surface modifier and toluene, continuously adding the brucite powder, the vinyl tri (beta-methoxyethoxy) silane surface modifier and the toluene into a vertical mill, and performing first superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃ to prepare 800-1500-mesh magnesium hydroxide modified fine powder;
s2, adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment to prepare 2500-8000-mesh magnesium hydroxide modified fine powder;
and S3, collecting, drying and packaging the treated magnesium hydroxide powder.
The magnesium hydroxide modified fine powder prepared in the embodiment is used as a halogen-free flame retardant and is applied to preparation of a low-smoke halogen-free cable material, and the low-smoke halogen-free cable material comprises the following raw materials in parts by weight: 88 parts of base resin, 12 parts of compatilizer, 165 parts of halogen-free flame retardant, 2 parts of coupling agent, 3 parts of lubricant and 1 part of antioxidant, and the cable material of the embodiment 1-3 is prepared respectively.
Setting a comparison group, wherein the magnesium hydroxide flame retardant of the comparison group is prepared by adopting the following method: selecting brucite powder with the particle size of 10-50 mm, continuously adding the brucite powder into a vertical mill, and performing a first superfine grinding treatment process at the temperature of 80-120 ℃ to prepare 800-1500-mesh magnesium hydroxide modified fine powder; then continuously conveying the mixture to an airflow mill for carrying out a second superfine grinding treatment process to prepare 2500-8000 mesh magnesium hydroxide modified fine powder.
The cable materials of examples 1-3 and the comparative cable material were tested for particle size distribution and performance, and the results are shown in the following table:
the cable extrusion effect is shown in fig. 1-4.
According to experimental results, the method disclosed by the invention has the advantages that the superfine grinding and mechanochemical modification integrated treatment are carried out on the magnesium hydroxide, so that the cable material prepared from the magnesium hydroxide flame retardant obtained after the grinding treatment is more excellent in performance, finer in surface particle size distribution, smoother, finer and more exquisite, and more excellent in elongation and melt index performance, and has popularization and use values.
In conclusion, the process for preparing the magnesium hydroxide flame retardant by integrating the superfine powder and the surface modification is simple, convenient to operate, high in efficiency, high in yield, low in energy consumption, environment-friendly and pollution-free, and can be widely applied to the industrial production process; the modified superfine magnesium hydroxide prepared by the invention improves the compatibility with a high polymer material, and obviously improves the mechanical property, the processing fluidity, the flame retardant property and the like of a high polymer composite material.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A method for superfine grinding and surface modification of magnesium hydroxide is to prepare a magnesium hydroxide flame retardant by a vertical mill/jet mill twice grinding and twice mechanochemical reaction modification integrated process, and is characterized by comprising the following steps:
s1, selecting brucite powder with the particle size of 10-50 mm, a surface modifier and a solvent, continuously adding the brucite powder, the surface modifier and the solvent into a vertical mill, and performing first superfine grinding and mechanochemical modification integrated treatment at the temperature of 80-120 ℃;
s2, adding the modified fine powder subjected to the first superfine grinding and mechanochemical modification integrated treatment into a continuous air flow mill, and carrying out second superfine grinding and mechanochemical modification integrated treatment;
and S3, collecting, drying and packaging the treated magnesium hydroxide powder.
2. The method of claim 1, wherein the magnesium hydroxide is further processed by the following steps: in step S1, the particle size of the modified magnesium hydroxide fine powder after the first integrated treatment of superfine grinding and mechanochemical modification is 800-1500 meshes; in step S2, the particle size of the modified magnesium hydroxide fine powder after the second integrated treatment of ultrafine grinding and mechanochemical modification is 2500-8000 meshes.
3. The method of claim 1, wherein the magnesium hydroxide is further processed by the following steps: in step S1, the surface modifier is one or more of stearic acid, organic carboxylate, silane coupling agent RSiX3, titanate coupling agent and phosphate coupling agent, and the solvent is one or more of organic additives such as absolute ethyl alcohol, acetone and toluene.
4. The method of claim 3, wherein the magnesium hydroxide is further processed by the following steps: the silane modifier is RSiX3, wherein R is amino, sulfydryl, vinyl, epoxy group, cyano or methacryloxy, and X is halogen, alkoxy or acyloxy.
5. The method of claim 1, wherein the magnesium hydroxide is further processed by the following steps: in step S1, the dosage of the surface modifier is 0.5-5% of the brucite powder by mass, and the dosage of the solvent is 0.5-2 times of the surface modifier by mass.
6. An application of magnesium hydroxide superfine and surface modification method, comprising the magnesium hydroxide prepared by the method of claims 1 to 5, applied to low smoke zero halogen cable material, characterized in that: the low-smoke halogen-free cable material comprises the following raw materials in parts by weight: 88 parts of base resin, 12 parts of compatilizer, 165 parts of halogen-free flame retardant, 2 parts of coupling agent, 3 parts of lubricant and 1 part of antioxidant.
7. The use of the method of claim 6 for the ultrafining and surface modification of magnesium hydroxide, wherein: the halogen-free flame retardant is magnesium hydroxide modified fine powder, the compatilizer is maleic anhydride grafted polyethylene, the lubricant is one or more of polyethylene wax, silicone powder and methyl silicone oil, and the antioxidant is a mixture of pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and distearyl thiodipropionate according to a mass ratio of 3: 4.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115193569A (en) * | 2022-07-26 | 2022-10-18 | 一夫科技股份有限公司 | Preparation method of superfine calcium sulfate |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102352130A (en) * | 2011-08-17 | 2012-02-15 | 太原理工大学 | Ball milling modification method for metal hydroxide fire retardant |
| CN103665939A (en) * | 2013-12-27 | 2014-03-26 | 江苏艾特克阻燃材料有限公司 | Method for integrally preparing high-dispersity ultrafine magnesium hydroxide flame retardant |
| CN103724792A (en) * | 2014-01-05 | 2014-04-16 | 陈旭 | Low-smoke zero-halogen environment-friendly EVA/LLDPE flame resistant composite material |
| CN103739927A (en) * | 2013-12-31 | 2014-04-23 | 上海至正道化高分子材料有限公司 | Formula of irradiation crosslinking low-smoke zero-halogen cable material with temperature resistance level of 150 DEG C and preparation method |
| CN104945728A (en) * | 2015-07-27 | 2015-09-30 | 上海至正道化高分子材料股份有限公司 | Low-smoke zero-halogen flame-retardant sheathing material for ultra-high-voltage cable and preparation method of sheathing material |
| CN108285552A (en) * | 2017-12-27 | 2018-07-17 | 江苏艾特克阻燃材料有限公司 | A kind of modified magnesium hydroxide, method of modifying and application |
| CN112266528A (en) * | 2020-09-28 | 2021-01-26 | 杭州融融通讯材料有限公司 | Combustion crusting halogen-free low-smoke high-flame-retardant cable material and preparation method thereof |
-
2022
- 2022-01-06 CN CN202210011604.0A patent/CN114292532B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102352130A (en) * | 2011-08-17 | 2012-02-15 | 太原理工大学 | Ball milling modification method for metal hydroxide fire retardant |
| CN103665939A (en) * | 2013-12-27 | 2014-03-26 | 江苏艾特克阻燃材料有限公司 | Method for integrally preparing high-dispersity ultrafine magnesium hydroxide flame retardant |
| CN104592790A (en) * | 2013-12-27 | 2015-05-06 | 江苏艾特克阻燃材料有限公司 | Method for controlling and modifying grain diameter of magnesium hydrate |
| CN103739927A (en) * | 2013-12-31 | 2014-04-23 | 上海至正道化高分子材料有限公司 | Formula of irradiation crosslinking low-smoke zero-halogen cable material with temperature resistance level of 150 DEG C and preparation method |
| CN103724792A (en) * | 2014-01-05 | 2014-04-16 | 陈旭 | Low-smoke zero-halogen environment-friendly EVA/LLDPE flame resistant composite material |
| CN104945728A (en) * | 2015-07-27 | 2015-09-30 | 上海至正道化高分子材料股份有限公司 | Low-smoke zero-halogen flame-retardant sheathing material for ultra-high-voltage cable and preparation method of sheathing material |
| CN108285552A (en) * | 2017-12-27 | 2018-07-17 | 江苏艾特克阻燃材料有限公司 | A kind of modified magnesium hydroxide, method of modifying and application |
| CN112266528A (en) * | 2020-09-28 | 2021-01-26 | 杭州融融通讯材料有限公司 | Combustion crusting halogen-free low-smoke high-flame-retardant cable material and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115193569A (en) * | 2022-07-26 | 2022-10-18 | 一夫科技股份有限公司 | Preparation method of superfine calcium sulfate |
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