Flame-retardant polyethylene master batch filled with magnesium hydroxide and preparation method of flame-retardant polyethylene master batch

Abstract

The invention provides a flame-retardant polyethylene master batch filled with magnesium hydroxide and a preparation method of the flame-retardant polyethylene master batch, and relates to the field of flame-retardant materials. The flame-retardant polyethylene master batch filled with magnesium hydroxide comprises the following raw materials in parts by mass: 8-20 parts of linear low-density polyethylene, 3-6 parts of an ethylene-octylene copolymer, 60-80 parts of modified magnesium hydroxide powder, 8-12 parts of montmorillonite powder, 3-5 parts of zinc borate, 2-5 parts of graphite powder, 1-4 parts of a lubricant, 4-8 parts of a coupling agent, 2-4 parts of barium stearate and 0.5-2 parts of an antioxidant. Compared with a common polyethylene material, the flame-retardant polyethylene master batch filled with magnesium hydroxide prepared by the invention has higher flame retardance, smoke suppression and carbon forming properties, also improves the dripping resistance of the polyethylene material, and can be used for preparing products such as polyethylene wires and cables, polyethylene foam boards, polyethylene pipes and the like.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, and in particular to a flame retardant polyethylene masterbatch filled with magnesium hydroxide and its preparation method. Background Technology

[0002] With economic development and the continuous improvement of people's living standards, polyethylene polymer materials have been widely used. Polyethylene (PE) is a polymer formed by polymerizing ethylene monomers. As one of the five major general-purpose plastics, it has good physical and mechanical properties and excellent electrical insulation properties. In addition, cross-linked polyethylene can be formed by chemical methods or irradiation to improve the strength, wear resistance, and heat resistance of polyethylene. Its applications are very wide. Therefore, there are certain requirements for the flame retardant properties of polyethylene. It can be used to prepare flame retardant filler masterbatch for use in wire and cable materials, foam materials, pipes and other fields.

[0003] Magnesium hydroxide (Mg(OH)2) is a white amorphous or crystalline solid, appearing as a white powder. It crystallizes in flake or fibrous form and has a melting point of approximately 350 degrees Celsius. When heated, it releases water, absorbs heat, and lowers the temperature of its surrounding environment, thus achieving a flame-retardant effect. It is widely used as a flame retardant, possessing multiple functions including flame retardancy, smoke suppression, charring, anti-dripping, and filling. It also imparts non-toxicity and non-corrosiveness to materials, making it one of the most popular and well-regarded inorganic flame retardants in recent years. However, directly using magnesium hydroxide as a filler is difficult to disperse, significantly impacting subsequent mechanical properties, and also generates a lot of dust and is environmentally unfriendly. This invention selects magnesium hydroxide as the main inorganic flame retardant to prepare a special flame-retardant filler masterbatch for polyethylene. Summary of the Invention

[0004] The purpose of this invention is to provide a flame-retardant polyethylene masterbatch filled with magnesium hydroxide and its preparation method, so as to improve the properties of halogen-free flame retardancy, smoke suppression, char formation and anti-dripping in wire and cable materials, foam materials, pipes and other fields.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a flame-retardant polyethylene masterbatch filled with magnesium hydroxide, comprising the following components in parts by weight: The composition includes 8-20 parts of linear low-density polyethylene, 3-6 parts of ethylene-octene copolymer, 60-80 parts of modified magnesium hydroxide powder, 8-12 parts of montmorillonite powder, 3-5 parts of zinc borate, 2-5 parts of graphite powder, 1-4 parts of lubricant, 4-8 parts of coupling agent, 2-4 parts of barium stearate, and 0.5-2 parts of antioxidant.

[0006] Preferably, the linear low-density polyethylene has a density of 0.910~0.940 g / cm³. 3 ; The octene monomer content in the ethylene-octene copolymer is >20%.

[0007] Preferably, the modified magnesium hydroxide powder is prepared by directly modifying the surface of magnesium hydroxide using a silane coupling agent; The particle size of the magnesium hydroxide powder is 1.5~2.2μm; The silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-diethylenetriaminopropyltrimethoxysilane and γ-aminopropylmethyldiethoxysilane; The mass ratio of the silane coupling agent to magnesium hydroxide powder is 7~12:1000; The surface modification temperature is 80~110℃, and the surface modification time is 10~30min.

[0008] Preferably, the montmorillonite powder has a particle size of 0.5~2μm and a density of 2~2.7g / cm³. 3 ; The zinc borate has a particle size of 5-7 μm and a density of 2.65-2.71 g / cm³. 3 ; The graphite powder has a particle size of 0.8~1.2μm and a carbon content of 90~98%.

[0009] Preferably, the lubricant comprises one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, stearic acid, and solid paraffin wax; The coupling agent includes one or more of aluminate coupling agents, silane coupling agents, and titanate coupling agents; The antioxidant is antioxidant 1010, antioxidant 3114 or antioxidant 168.

[0010] The present invention also provides a method for preparing the aforementioned magnesium hydroxide-filled flame-retardant polyethylene masterbatch, comprising the following steps: 1) A mixture is prepared by mixing linear low-density polyethylene, ethylene-octene copolymer, barium stearate, coupling agent and antioxidant; 2) The mixture is mixed with modified magnesium hydroxide powder, montmorillonite powder, zinc borate, graphite powder and lubricant, heated and then melt-extruded, cooled and granulated to obtain flame-retardant polyethylene masterbatch filled with magnesium hydroxide.

[0011] Preferably, the mixing temperature in step 1) is 80~90℃, the mixing time is 5~10min, and the mixing speed is 600~800r / min.

[0012] Preferably, the temperature of the mixing and heating in step 2) is 180~210℃, the mixing and heating time is 10~15min, and the mixing and heating speed is 1200~1800r / min.

[0013] Preferably, the melt extrusion in step 2) is performed using a twin-screw extruder; The length-to-diameter ratio of the twin-screw extruder is 42~54:1; The temperature settings of the twin-screw extruder are as follows: pre-melting zone 150~160℃, first melting zone 180~210℃, first high-temperature shearing zone 190~215℃, second high-temperature shearing zone 210~225℃, second melting zone 215~230℃, and discharge port melting zone 200~215℃. The rotational speed of the twin-screw extruder is 260~300 r / min.

[0014] The present invention has at least the following beneficial effects: The flame-retardant polyethylene masterbatch filled with magnesium hydroxide prepared by this invention has higher flame retardancy, smoke suppression and char formation properties compared with ordinary polyethylene materials, and also improves the anti-dripping properties of polyethylene materials. It can be used to prepare polyethylene wires and cables, polyethylene foam boards and polyethylene pipes and other products. Detailed Implementation

[0015] This invention provides a flame-retardant polyethylene masterbatch filled with magnesium hydroxide, comprising the following components in parts by weight: The composition comprises 8-20 parts linear low-density polyethylene, 3-6 parts ethylene-octene copolymer, 60-80 parts modified magnesium hydroxide powder, 8-12 parts montmorillonite powder, 3-5 parts zinc borate, 2-5 parts graphite powder, 1-4 parts lubricant, 4-8 parts coupling agent, 2-4 parts barium stearate, and 0.5-2 parts antioxidant; preferably, it comprises 10-18 parts linear low-density polyethylene, 3.5-5.5 parts ethylene-octene copolymer, 63-78 parts modified magnesium hydroxide powder, 9-11 parts montmorillonite powder, 3.5-4.5 parts zinc borate, 2.5-4.5 parts graphite powder, 1.5-3.5 parts lubricant, 4.5-7.5 parts coupling agent, 2.5-3.5 parts barium stearate, and 0.8-1 parts antioxidant. 8 parts; more preferably, 12-16 parts of linear low-density polyethylene, 4-5 parts of ethylene-octene copolymer, 65-75 parts of modified magnesium hydroxide powder, 9-11 parts of montmorillonite powder, 3.8-4.2 parts of zinc borate, 3-4 parts of graphite powder, 2-3 parts of lubricant, 5-7 parts of coupling agent, 2.8-3.3 parts of barium stearate, and 1-1.6 parts of antioxidant; more preferably, 14-15 parts of linear low-density polyethylene, 4.5-5 parts of ethylene-octene copolymer, 68-72 parts of modified magnesium hydroxide powder, 10-11 parts of montmorillonite powder, 4 parts of zinc borate, 3.5-4 parts of graphite powder, 2-2.5 parts of lubricant, 5-6 parts of coupling agent, 3 parts of barium stearate, and 1.2-1.4 parts of antioxidant.

[0016] In this invention, the linear low-density polyethylene is a milky white, tasteless, odorless, non-toxic, matte, waxy granule with a density of 0.910~0.940 g / cm³. 3 The preferred value is 0.920~0.930 g / cm³. 3 Further preferably, it is 0.925~0.928 g / cm³. 3 More preferably, it is 0.926-0.927 g / cm³. 3 .

[0017] In this invention, the mass percentage of octene monomer in the ethylene-octene copolymer is >20%, preferably 25-42%, more preferably 28-38%, and even more preferably 30-35%.

[0018] In this invention, the modified magnesium hydroxide powder is prepared by directly modifying the surface of magnesium hydroxide with a silane coupling agent. The magnesium hydroxide powder is a white powder with a flaky or fibrous structure and a particle size of 1.5~2.2μm, preferably 1.6~2.1μm, more preferably 1.7~2.0μm, and even more preferably 1.8~1.9μm. The silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-diethylenetriaminopropyltrimethoxysilane and γ-aminopropylmethyldiethoxysilane; The mass ratio of the silane coupling agent to magnesium hydroxide powder is 7~12:1000; The surface modification temperature is 80~110℃, and the surface modification time is 10~30min.

[0019] In this invention, the montmorillonite powder has a particle size of 0.5~2.0 μm, preferably 0.8~1.8 μm, more preferably 1.0~1.6 μm, and even more preferably 1.2~1.4 μm; and a density of 2~2.7 g / cm³. 3 The preferred concentration is 2.1~2.6 g / cm³. 3 Further preferably, it is 2.2~2.5 g / cm³. 3 More preferably, it is 2.3~2.4 g / cm³. 3 .

[0020] In this invention, the zinc borate has a particle size of 5-7 μm, preferably 5.5-6.5 μm, and more preferably 5.8-6.2 μm; and a density of 2.65-2.71 g / cm³. 3 The preferred value is 2.66~2.70 g / cm³. 3 Further preferred values ​​are 2.67~2.69 g / cm³. 3 More preferably, it is 2.68~2.69 g / cm³. 3 .

[0021] In this invention, the graphite powder has a particle size of 0.8~1.2μm, preferably 0.9~1.2μm, more preferably 1.0~1.2μm, and even more preferably 1.1~1.2μm; and a carbon content of 90~98%, preferably 92~98%, and even more preferably 94~96%.

[0022] In this invention, the lubricant includes one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, stearic acid, and solid paraffin.

[0023] In this invention, the coupling agent includes one or more of aluminate coupling agents, silane coupling agents, and titanate coupling agents.

[0024] In this invention, the antioxidant is antioxidant 1010, antioxidant 3114 or antioxidant 168.

[0025] The present invention also provides a method for preparing the aforementioned magnesium hydroxide-filled flame-retardant polyethylene masterbatch, comprising the following steps: 1) A mixture is prepared by mixing linear low-density polyethylene, ethylene-octene copolymer, barium stearate, coupling agent and antioxidant; 2) The mixture is mixed with modified magnesium hydroxide powder, montmorillonite powder, zinc borate, graphite powder and lubricant, heated and then melt-extruded, cooled and granulated to obtain flame-retardant polyethylene masterbatch filled with magnesium hydroxide.

[0026] In this invention, the mixing temperature in step 1) is 80~90℃, preferably 82~88℃, more preferably 84~86℃, and even more preferably 85℃; the mixing time is 5~10min, preferably 6~9min, and even more preferably 7~8min; the mixing speed is 600~800r / min, preferably 650~750r / min, more preferably 680~720r / min, and even more preferably 700r / min.

[0027] In this invention, the temperature of the mixed heating in step 2) is 180~210℃, preferably 185~205℃, more preferably 190~200℃, and even more preferably 195~200℃; the time of mixed heating is 10~15min, which can be 10min, 11min, 12min, 13min, 14min or 15min; the rotation speed of the mixed heating is 1200~1800r / min, preferably 1300~1700r / min, more preferably 1400~1600r / min, and even more preferably 1500r / min.

[0028] In this invention, the melt extrusion described in step 2) is performed using a twin-screw extruder; The length-to-diameter ratio of the twin-screw extruder is 42~54:1, preferably 44~52:1, more preferably 46~50:1, and even more preferably 47~48:1.

[0029] In this invention, the temperature settings of the twin-screw extruder are as follows: pre-melting zone 150~160℃, first melting zone 180~210℃, first high-temperature shear zone 190~215℃, second high-temperature shear zone 210~225℃, second melting zone 215~230℃, and outlet melting zone 200~215℃; preferably, the pre-melting zone is 152~158℃, the first melting zone is 185~205℃, and the first high-temperature shear zone is 190~215℃. The temperature ranges from 5 to 210°C, with the second high-temperature shear zone at 213 to 222°C, the second melting zone at 218 to 227°C, and the outlet melting zone at 203 to 212°C. More preferably, the temperature ranges from 154 to 156°C, with the first melting zone at 190 to 200°C, the first high-temperature shear zone at 200 to 205°C, the second high-temperature shear zone at 215 to 220°C, the second melting zone at 220 to 225°C, and the outlet melting zone at 205 to 210°C.

[0030] In this invention, the rotational speed of the twin-screw extruder is 260~300 r / min, preferably 270~290 r / min, and more preferably 280 r / min.

[0031] The technical solutions provided by the present invention will be 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.

[0032] Example 1

[0033] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0034] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 3 12 parts of modified magnesium hydroxide powder, 4 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 1010) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 60 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 3 8 parts, zinc borate (particle size 2.5μm, density 3.64g / cm³) 3 Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 15 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0035] Example 2

[0036] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0037] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 3 12 parts of modified magnesium hydroxide powder, 4 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 168) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 70 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 3 8 parts of zinc borate (particle size 2.5μm, density 3.64g / cm³) 3 Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 10 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0038] Example 3

[0039] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0040] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 312 parts of modified magnesium hydroxide powder, 4 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 1010) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 80 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 3 8 parts, zinc borate (particle size 2.5μm, density 3.64g / cm³) 3 Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 15 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0041] Example 4

[0042] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0043] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 3 15 parts of modified magnesium hydroxide powder, 5 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 1010) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 60 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 38 parts, zinc borate (particle size 2.5μm, density 3.64g / cm³) 3 Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 10 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0044] Example 5

[0045] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0046] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 3 15 parts of modified magnesium hydroxide powder, 5 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 1010) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 70 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 3 8 parts, zinc borate (particle size 2.5μm, density 3.64g / cm³) 3Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 15 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0047] Example 6

[0048] Preparation of modified magnesium hydroxide powder: Magnesium hydroxide powder with a particle size of 1.7 μm was mixed with γ-aminopropyltrimethoxysilane (manufactured by Jiangsu Chenguang Coupling Agent Co., Ltd.). The amount of γ-aminopropyltrimethoxysilane added was 9‰ of the mass of magnesium hydroxide powder. The modification was completed by reacting at 110℃ for 30 min to obtain modified magnesium hydroxide powder.

[0049] The dried low-density polyethylene (Yanshan Petrochemical, LD100BW, density 0.926 g / cm³) was used. 3 15 parts of modified magnesium hydroxide powder, 5 parts of POE (Dow 8401, octene content 24wt%), 2 parts of barium stearate (Guangzhou Yifeng Chemical Technology Co., Ltd., model: Yuejiang), 5 parts of coupling agent (Shandong Sodium Magnesium New Material Co., Ltd., model: KH-550), and 0.5 parts of antioxidant (Lialon Supply Chain Management Co., Ltd., model: Oxidant 1010) were placed in a temperature-controlled high-speed mixer and mixed for 8 minutes at 85℃ and 600 r / min. Then, 80 parts of modified magnesium hydroxide powder and montmorillonite powder (particle size 2.7μm, density 2.65 g / cm³) were added. 3 8 parts, zinc borate (particle size 2.5μm, density 3.64g / cm³) 3Three parts of magnesium hydroxide-filled flame-retardant polyethylene masterbatch were added to a high-speed mixer at a speed of 1800 r / min, 3 parts of graphite powder (1.8 μm particle size, 99% carbon content) and 2 parts of lubricant (Clariant: Licowax PE520). The mixture was stirred for 15 minutes at 200℃, then cooled to 40℃ to obtain a premix. The premix was then fed into a twin-screw extruder with a length-to-diameter ratio of 48:1. After melt extrusion, cooling, and granulation, the material was obtained. The temperatures of each zone of the twin-screw extruder were as follows: pre-melt zone 160℃, first melt zone 200℃, first high-temperature shear zone 210℃, second high-temperature shear zone 220℃, second melt zone 220℃, and discharge port melt zone 210℃. The screw speed was 300 r / min.

[0050] Comparative Example 1

[0051] This is flame-retardant PE masterbatch (6001RM10) produced by Guangdong Jushi Chemical Co., Ltd.

[0052] The performance of the flame-retardant polyethylene masterbatch and flame-retardant PE masterbatch filled with magnesium hydroxide in Examples 1-6 and Comparative Example 1 was tested, and the test methods are as follows: Tensile strength was tested according to GB / T 1040.1-2018; Notched impact strength was tested according to GB / T 1843-2008; Bending strength was tested according to GB / T 9341-2008; Flame retardant properties are tested according to UL94.

[0053] The test results are shown in Table 1.

[0054] Table 1. Performance test results of flame-retardant polyethylene masterbatch and flame-retardant PE masterbatch filled with magnesium hydroxide in Examples 1-6 and Comparative Example 1.

[0055] As can be seen from Table 1, the mechanical properties of the flame-retardant polyethylene masterbatch of the present invention are significantly better than those of the flame-retardant PE masterbatch produced by Guangdong Jushi Chemical Co., Ltd., the melt flow rate is also lower, the anti-falling effect is better, the flame retardant performance reaches V0 level, and the maximum smoke density is also lower, indicating that the flame retardant and smoke suppression effect is better and the overall performance is more superior.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A flame-retardant polyethylene masterbatch filled with magnesium hydroxide, characterized in that, The components include the following parts by mass: The composition includes 8-20 parts of linear low-density polyethylene, 3-6 parts of ethylene-octene copolymer, 60-80 parts of modified magnesium hydroxide powder, 8-12 parts of montmorillonite powder, 3-5 parts of zinc borate, 2-5 parts of graphite powder, 1-4 parts of lubricant, 4-8 parts of coupling agent, 2-4 parts of barium stearate, and 0.5-2 parts of antioxidant.

2. The flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 1, characterized in that, The linear low-density polyethylene has a density of 0.910~0.940 g / cm³. 3 ; The octene monomer content in the ethylene-octene copolymer is >20%.

3. The flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 2, characterized in that, The modified magnesium hydroxide powder is prepared by directly modifying the surface of magnesium hydroxide with a silane coupling agent. The particle size of the magnesium hydroxide powder is 1.5~2.2μm; The silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-diethylenetriaminopropyltrimethoxysilane and γ-aminopropylmethyldiethoxysilane; The mass ratio of the silane coupling agent to magnesium hydroxide powder is 7~12:1000; The surface modification temperature is 80~110℃, and the surface modification time is 10~30min.

4. A flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to any one of claims 1 to 3, characterized in that, The montmorillonite powder has a particle size of 0.5~2μm and a density of 2~2.7g / cm³. 3 ; The zinc borate has a particle size of 5-7 μm and a density of 2.65-2.71 g / cm³. 3 ; The graphite powder has a particle size of 0.8~1.2μm and a carbon content of 90~98%.

5. The flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 4, characterized in that, The lubricant includes one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, stearic acid, and solid paraffin wax; The coupling agent includes one or more of aluminate coupling agents, silane coupling agents, and titanate coupling agents; The antioxidant is antioxidant 1010, antioxidant 3114 or antioxidant 168.

6. A method for preparing a flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to any one of claims 1 to 5, characterized in that, Includes the following steps: 1) A mixture is prepared by mixing linear low-density polyethylene, ethylene-octene copolymer, barium stearate, coupling agent and antioxidant; 2) The mixture is mixed with modified magnesium hydroxide powder, montmorillonite powder, zinc borate, graphite powder and lubricant, heated and then melt-extruded, cooled and granulated to obtain flame-retardant polyethylene masterbatch filled with magnesium hydroxide.

7. The method for preparing a flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 6, characterized in that, The mixing temperature in step 1) is 80~90℃, the mixing time is 5~10min, and the mixing speed is 600~800r / min.

8. The method for preparing a flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 7, characterized in that, The mixing and heating temperature in step 2) is 180~210℃, the mixing and heating time is 10~15min, and the mixing and heating speed is 1200~1800r / min.

9. The method for preparing a flame-retardant polyethylene masterbatch filled with magnesium hydroxide according to claim 7, characterized in that, The melt extrusion described in step 2) is performed using a twin-screw extruder; The length-to-diameter ratio of the twin-screw extruder is 42~54:1; The temperature settings of the twin-screw extruder are as follows: pre-melting zone 150~160℃, first melting zone 180~210℃, first high-temperature shearing zone 190~215℃, second high-temperature shearing zone 210~225℃, second melting zone 215~230℃, and discharge port melting zone 200~215℃. The rotational speed of the twin-screw extruder is 260~300 r / min.

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