Polyethylene flame-retardant master batch and production process thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a polyethylene flame-retardant master batch and a production process thereof. The polyethylene flame-retardant master batch is prepared from the following raw materials in parts by weight: 50 to 60 parts of polyethylene, 10 to 20 parts of hydroxymethyl phosphinic acid, 15 to 20 parts of HDPE-g-MAH, 0.8 to 1.5 parts of an initiator, 1 to 2 parts of an antioxidant and 3 to 6 parts of functional particles. The polyethylene is selected from high-density polyethylene, and the melt index of the polyethylene is 7-20g / 10min under the conditions of 190 DEG C and 2.16 kg; the polyethylene flame-retardant master batch produced by the invention not only can effectively enhance the flame retardant property of a polyethylene product, but also can effectively improve the anti-aging property of the polyethylene product; and the service life of the polyethylene product is prolonged to a certain extent while the quality of the polyethylene product is ensured.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polyethylene flame retardant masterbatch and its production process. Background Technology

[0002] Polyethylene (PE) is widely used in many fields due to its excellent physical properties, chemical stability, and processing performance. However, PE is highly flammable, and in many applications with high fire protection requirements, its flammability poses a significant safety hazard, limiting its further widespread use. Traditional flame-retardant treatment methods, such as directly adding flame retardants, have many problems, such as poor dispersion of flame retardants in the polyethylene matrix and poor compatibility with the matrix, leading to a decline in product performance, such as deterioration of mechanical properties and surface defects. The use of masterbatches can effectively solve the aforementioned technical problems. While existing polyethylene flame-retardant masterbatches have certain flame-retardant properties, their flame-retardant performance is not ideal and needs further improvement. Moreover, their properties are relatively singular, often only possessing a certain degree of flame retardancy and failing to positively influence or improve other properties of polyethylene products, which can negatively impact the quality of polyethylene products.

[0003] Therefore, the present invention provides a polyethylene flame retardant masterbatch and its production process, which aims to improve the flame retardant and anti-aging properties of polyethylene masterbatch and polyethylene-related products, and extend their service life to a certain extent while ensuring their quality. Summary of the Invention

[0004] The purpose of this invention is to provide a polyethylene flame-retardant masterbatch and its production process. The produced polyethylene flame-retardant masterbatch can not only effectively enhance the flame-retardant properties of polyethylene products, but also effectively improve their anti-aging properties. While ensuring the quality of polyethylene products, it also extends their service life to a certain extent.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A polyethylene flame retardant masterbatch is composed of the following raw materials in parts by weight: 50-60 parts polyethylene, 10-20 parts hydroxymethylphosphonic acid, 15-20 parts HDPE-g-MAH, 0.8-1.5 parts initiator, 1-2 parts antioxidant and 3-6 parts functional microparticles.

[0007] Furthermore, the polyethylene is selected as high-density polyethylene, and its melt index at 190°C and 2.16 kg is 7-20 g / 10 min.

[0008] Furthermore, the initiator is selected from any one of dicumyl peroxide, benzoyl peroxide, and tert-butyl peroxide.

[0009] Furthermore, the antioxidant is selected from any one of antioxidant 1010, antioxidant 168, and antioxidant DSTP.

[0010] Furthermore, the method for preparing the functional microparticles includes the following steps:

[0011] Step 1: Add 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid to oxalyl chloride at a solid-liquid ratio of 20-30 g / L. Reflux the reaction until no irritating gas is released, then terminate the reaction. Remove excess oxalyl chloride from the product components under reduced pressure. The remaining components are referred to as grafting agents.

[0012] Step 2: Disperse the pretreated inorganic carrier in a mixed solvent consisting of equal volumes of ethanol and N,N-dimethylformamide at a dosage ratio of 20-50 g / L. Then add grafting agent at a mass ratio of 0.5-0.6 times that of the pretreated inorganic carrier and ammonium polyphosphate at a mass ratio of 0.3-0.5 times. Stir until homogeneous, then add benzopyridine at a mass ratio of 2-4 times that of the grafting agent. After homogeneous dispersion, stir and react under nitrogen protection for 20-25 hours. After the reaction is complete, filter the product components. Wash the filter cake alternately with ethanol and N,N-dimethylformamide 3-4 times and then vacuum dry to obtain functional microparticles.

[0013] Furthermore, the preparation method of the pretreated inorganic carrier is as follows: the inorganic carrier is uniformly dispersed in toluene at a solid-liquid ratio of 10-30 g / L, 5-8% by volume of 3-aminopropyltrimethoxysilane is added, and after mixing and stirring evenly, 0.2-0.3 times the volume of 3-aminopropyltrimethoxysilane is added, and the reaction is kept at 70-85°C for 10-15 h; after the reaction is completed, the product components are filtered, washed and vacuum dried in sequence to obtain the pretreated inorganic carrier.

[0014] Furthermore, the inorganic carrier is prepared as follows: spherical magnesium hydroxide is added to an ethanol solution of 0.05–0.1 mol / L cerium nitrate at a dosage ratio of 5–15 g / L, and the mixture is stirred for 20–30 min. Then, a 0.02–0.05 mol / L hexamethylenetetramine solution is added dropwise while stirring. The resulting dispersion is then heated to 70–80 °C and stirred at a rate of 800–1200 r / min for 3–5 h. After the reaction is complete, the product components are filtered, and the filter cake is washed alternately with deionized water and anhydrous ethanol 3–4 times before being vacuum dried. The resulting inorganic carrier is the inorganic carrier. The molar ratio of cerium nitrate to hexamethylenetetramine in the dispersion is 1:3–5.

[0015] Furthermore, the method for preparing the spherical magnesium hydroxide includes the following steps:

[0016] Step 1: Add 0.2-0.4 times the volume of glycerol and 0.3-0.5 times the volume of sodium citrate aqueous solution to a 2-5 mol / L magnesium sulfate aqueous solution. Then, while stirring, add sodium hydroxide aqueous solution dropwise. Stop adding alkali when a white precipitate forms, and continue stirring until the white precipitate disappears. Store the resulting first mixed component for later use. The concentration of the sodium citrate aqueous solution is 0.04-0.06 mol / L.

[0017] Step 2: Seal 25-28 wt% ammonia water with perforated plastic wrap and place it together with an equal volume of the first mixed component in a sealed container. Keep the mixture at 35-45°C for 40-50 hours. After the reaction is complete, perform solid-liquid separation on the product components. Wash the filter cake with deionized water 5-8 times. Test the washing liquid with a barium ion solution until no white precipitate is formed. Then wash it with anhydrous ethanol 3-5 times. After washing, dry the filter cake to obtain spherical magnesium hydroxide.

[0018] Furthermore, the concentration of the sodium hydroxide aqueous solution is 0.01–0.02 mol / L, the dropping rate is 10–15 drops / min, and the stirring rate is 100–150 r / min.

[0019] A production process for polyethylene flame retardant masterbatch includes the following steps: accurately weighing each raw material required for preparing polyethylene flame retardant masterbatch, mixing and stirring each raw material evenly, feeding it into a twin-screw extruder, and extruding and granulating it at a temperature of 170-185°C to obtain polyethylene flame retardant masterbatch.

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

[0021] This invention uses magnesium sulfate aqueous solution, glycerol, sodium citrate aqueous solution, and ammonia as raw materials to prepare spherical magnesium hydroxide with a relatively rough surface. Then, the spherical magnesium hydroxide is added to an ethanol solution of cerium nitrate, and hexamethylenetetramine solution is added dropwise while stirring. After uniform dispersion, the mixture is kept at a constant temperature and stirred for reaction, ultimately coating the surface of the spherical magnesium hydroxide with a dense nano-cerium oxide film, thus obtaining an inorganic carrier. The inorganic carrier is dispersed in toluene, and 3-aminopropyltrimethoxysilane and triethylamine are added. After a temperature-controlled reaction, 3-aminopropyltrimethoxysilane is introduced onto the surface of the inorganic carrier, resulting in a pretreated inorganic carrier.

[0022] Furthermore, this invention uses 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid and oxalyl chloride as raw materials to prepare a grafting agent via reflux reaction. The pretreated inorganic carrier is dispersed in a mixed solvent, and the grafting agent and ammonium polyphosphate are added. After stirring evenly, under the action of triethylamine, the grafting agent with excellent antioxidant properties is effectively grafted onto the surface of the pretreated inorganic carrier through the "bridging" effect of 3-aminopropyltrimethoxysilane, forming a three-dimensional network structure of antioxidant film. Simultaneously, the added ammonium polyphosphate undergoes ion exchange with the surface of the pretreated inorganic carrier, ultimately loading the pretreated inorganic carrier with the grafting agent bonded to its surface onto the ammonium polyphosphate surface. This achieves an effective combination of ammonium polyphosphate and the pretreated inorganic carrier, yielding functional microparticles.

[0023] The functional microparticles prepared in this invention are composed of an inorganic carrier, a grafting agent bonded to its surface, and ammonium polyphosphate. The inorganic carrier has a spherical core-shell structure with spherical magnesium hydroxide as the "core" and nano-cerium oxide as the "shell," which gives it excellent flame retardant properties and a certain degree of resistance to ultraviolet aging. Furthermore, the grafting agent grafted onto the surface of the inorganic carrier synergistically improves the anti-aging properties of the functional microparticles with the nano-cerium oxide film. Meanwhile, the synergistic effect between ammonium polyphosphate, spherical magnesium hydroxide, and nano-cerium oxide film significantly enhances the flame retardant properties of the functional microparticles. The resulting functional microparticles not only effectively enhance the flame retardant properties of polyethylene masterbatch but also effectively improve its anti-aging properties.

[0024] In summary, the polyethylene flame-retardant masterbatch produced by this invention not only effectively enhances the flame-retardant properties of polyethylene products but also effectively improves their anti-aging properties. While ensuring the quality of polyethylene products, it also extends their service life to a certain extent. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A polyethylene flame retardant masterbatch is composed of the following raw materials in parts by weight: 50 parts polyethylene, 10 parts hydroxymethylphosphonic acid, 15 parts HDPE-g-MAH, 0.8 parts dicumyl peroxide, 1 part antioxidant 1010 and 3 parts functional microparticles.

[0028] High-density polyethylene was selected, and its melt index was 15 g / 10 min at 190℃ and 2.16 kg.

[0029] The preparation method of functional microparticles includes the following steps:

[0030] Step 1: Add 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid to oxalyl chloride at a solid-liquid ratio of 20 g / L. Reflux the reaction until no irritating gas is released, then terminate the reaction. Remove excess oxalyl chloride from the product components by vacuum distillation. The remaining components are referred to as grafting agents.

[0031] The second step involves dispersing the pretreated inorganic carrier in a mixed solvent consisting of equal volumes of ethanol and N,N-dimethylformamide at a dosage ratio of 20 g / L. Then, grafting agent (0.5 times the mass of the pretreated inorganic carrier) and ammonium polyphosphate (0.3 times the mass of the pretreated inorganic carrier) are added and stirred until homogeneous. Next, benzopyridine (2 times the mass of the grafting agent) is added and dispersed evenly. The mixture is then stirred and reacted for 20 hours under nitrogen protection. After the reaction is complete, the product components are filtered. The filter cake is washed three times alternately with ethanol and N,N-dimethylformamide and then vacuum dried to obtain the functional microparticles.

[0032] The preparation method of the pretreated inorganic carrier is as follows: the inorganic carrier is uniformly dispersed in toluene at a solid-liquid ratio of 10 g / L, 3-aminopropyltrimethoxysilane (5% by volume of toluene) is added, and after mixing and stirring evenly, triethylamine (0.2 times the volume of 3-aminopropyltrimethoxysilane) is added, and the reaction is kept at 70℃ for 10 h. After the reaction is completed, the product components are filtered, washed and vacuum dried in sequence to obtain the pretreated inorganic carrier.

[0033] The inorganic carrier was prepared as follows: spherical magnesium hydroxide was added to a 0.05 mol / L cerium nitrate ethanol solution at a dosage ratio of 5 g / L. After mixing and stirring for 20 min, a 0.02 mol / L hexamethylenetetramine solution was added dropwise while stirring. The resulting dispersion was then heated to 70 °C and stirred at a rate of 800 r / min for 3 h. After the reaction was completed, the product components were filtered. The filter cake was washed three times alternately with deionized water and anhydrous ethanol and then vacuum dried to obtain the inorganic carrier. The molar ratio of cerium nitrate to hexamethylenetetramine in the dispersion was 1:3.

[0034] The preparation method of spherical magnesium hydroxide includes the following steps:

[0035] Step 1: Add 0.2 times the volume of glycerol and 0.3 times the volume of sodium citrate aqueous solution to a 2 mol / L magnesium sulfate aqueous solution. Then, while stirring, add sodium hydroxide aqueous solution dropwise. Stop adding alkali when a white precipitate forms, and continue stirring until the white precipitate disappears. Store the resulting first mixed component for later use. The concentration of the sodium citrate aqueous solution is 0.04 mol / L, and the concentration of the sodium hydroxide aqueous solution is 0.01 mol / L. The dropping rate is 10 drops / min, and the stirring speed is 100 r / min.

[0036] Step 2: Seal 25wt% ammonia water with perforated plastic wrap and place it together with an equal volume of the first mixed component in a sealed container. Keep the mixture at 35℃ for 40 hours. After the reaction is complete, perform solid-liquid separation on the product components. Wash the filter cake 5 times with deionized water. Test the washing liquid with a barium ion solution until no white precipitate is formed. Then wash it 3 times with anhydrous ethanol. After washing, dry the filter cake to obtain spherical magnesium hydroxide.

[0037] A production process for polyethylene flame retardant masterbatch includes the following steps: accurately weighing each raw material required for preparing polyethylene flame retardant masterbatch, mixing and stirring each raw material evenly, feeding it into a twin-screw extruder, and extruding and granulating it at a temperature of 180°C to obtain polyethylene flame retardant masterbatch.

[0038] Example 2

[0039] The production process of the polyethylene flame retardant masterbatch provided in this embodiment is basically the same as that in Embodiment 1, except that the specific composition of the raw materials and the preparation method of the functional microparticles are not exactly the same. The specific composition of the raw materials and the preparation method of the functional microparticles in this embodiment are as follows:

[0040] A polyethylene flame retardant masterbatch is composed of the following raw materials in parts by weight: 55 parts polyethylene, 15 parts hydroxymethylphosphonic acid, 15 parts HDPE-g-MAH, 1.2 parts benzoyl peroxide, 1.5 parts antioxidant 168 and 5 parts functional microparticles.

[0041] The preparation method of functional microparticles includes the following steps:

[0042] Step 1: Add 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid to oxalyl chloride at a solid-liquid ratio of 25 g / L. Reflux the reaction until no irritating gas is released, then terminate the reaction. Remove excess oxalyl chloride from the product components by vacuum distillation. The remaining components are referred to as grafting agents.

[0043] The second step involves dispersing the pretreated inorganic carrier in a mixed solvent consisting of equal volumes of ethanol and N,N-dimethylformamide at a dosage ratio of 40 g / L. Then, grafting agent (0.5 times the mass of the pretreated inorganic carrier) and ammonium polyphosphate (0.4 times the mass of the pretreated inorganic carrier) are added and stirred until homogeneous. Next, benzopyridine (3 times the mass of the grafting agent) is added and dispersed evenly. The mixture is then stirred and reacted for 25 hours under nitrogen protection. After the reaction is complete, the product components are filtered. The filter cake is washed three times alternately with ethanol and N,N-dimethylformamide and then vacuum dried to obtain the functional microparticles.

[0044] The preparation method of the pretreated inorganic carrier is as follows: the inorganic carrier is uniformly dispersed in toluene at a solid-liquid ratio of 20 g / L, 6% (by volume) of 3-aminopropyltrimethoxysilane is added, and after mixing and stirring evenly, 0.2 times the volume of 3-aminopropyltrimethoxysilane is added, and the reaction is kept at 80℃ for 12 h. After the reaction is completed, the product components are filtered, washed and vacuum dried in sequence to obtain the pretreated inorganic carrier.

[0045] The inorganic carrier was prepared as follows: spherical magnesium hydroxide was added to a 0.08 mol / L cerium nitrate ethanol solution at a dosage ratio of 10 g / L. After mixing and stirring for 25 min, a 0.03 mol / L hexamethylenetetramine solution was added dropwise while stirring. The resulting dispersion was then heated to 75 °C and stirred at a rate of 1000 r / min for 4 h. After the reaction was completed, the product components were filtered. The filter cake was washed four times alternately with deionized water and anhydrous ethanol and then vacuum dried to obtain the inorganic carrier. The molar ratio of cerium nitrate to hexamethylenetetramine in the dispersion was 1:4.

[0046] The preparation method of spherical magnesium hydroxide includes the following steps:

[0047] Step 1: Add 0.3 times the volume of glycerol and 0.4 times the volume of sodium citrate aqueous solution to a 3 mol / L magnesium sulfate aqueous solution. Then, while stirring, add sodium hydroxide aqueous solution dropwise. Stop adding alkali when a white precipitate forms, and continue stirring until the white precipitate disappears. Store the resulting first mixed component for later use. The concentration of the sodium citrate aqueous solution is 0.05 mol / L, and the concentration of the sodium hydroxide aqueous solution is 0.02 mol / L. The dropping rate is 15 drops / min, and the stirring rate is 150 r / min.

[0048] Step 2: Seal 28wt% ammonia water with perforated plastic wrap and place it together with an equal volume of the first mixed component in a sealed container. Keep the mixture at 40℃ for 45 hours. After the reaction is complete, perform solid-liquid separation on the product components. Wash the filter cake 6 times with deionized water. Test the washing liquid with a barium ion solution until no white precipitate is formed. Then wash it 4 times with anhydrous ethanol. After washing, dry the filter cake to obtain spherical magnesium hydroxide.

[0049] Example 3

[0050] The production process of the polyethylene flame retardant masterbatch provided in this embodiment is basically the same as that in Embodiment 1, except that the specific composition of the raw materials and the preparation method of the functional microparticles are not exactly the same. The specific composition of the raw materials and the preparation method of the functional microparticles in this embodiment are as follows:

[0051] A polyethylene flame retardant masterbatch is composed of the following raw materials in parts by weight: 60 parts polyethylene, 20 parts hydroxymethylphosphonic acid, 20 parts HDPE-g-MAH, 1.5 parts tert-butyl peroxide, 2 parts antioxidant DSTP, and 6 parts functional microparticles.

[0052] The preparation method of functional microparticles includes the following steps:

[0053] Step 1: Add 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid to oxalyl chloride at a solid-liquid ratio of 30 g / L. Reflux the reaction until no irritating gas is released, then terminate the reaction. Remove excess oxalyl chloride from the product components by vacuum distillation. The remaining components are referred to as grafting agents.

[0054] The second step involves dispersing the pretreated inorganic carrier in a mixed solvent consisting of equal volumes of ethanol and N,N-dimethylformamide at a dosage ratio of 50 g / L. Then, grafting agent (0.6 times the mass of the pretreated inorganic carrier) and ammonium polyphosphate (0.5 times the mass of the pretreated inorganic carrier) are added and stirred until homogeneous. Next, benzopyridine (4 times the mass of the grafting agent) is added and dispersed evenly. The mixture is then stirred and reacted for 25 hours under nitrogen protection. After the reaction is complete, the product components are filtered. The filter cake is washed four times alternately with ethanol and N,N-dimethylformamide and then vacuum dried to obtain the functional microparticles.

[0055] The preparation method of the pretreated inorganic carrier is as follows: the inorganic carrier is uniformly dispersed in toluene at a solid-liquid ratio of 30 g / L, 3-aminopropyltrimethoxysilane (8% by volume of toluene) is added, and after mixing and stirring evenly, triethylamine (0.3 times the volume of 3-aminopropyltrimethoxysilane) is added, and the reaction is kept at 85℃ for 15 h. After the reaction is completed, the product components are filtered, washed and vacuum dried in sequence to obtain the pretreated inorganic carrier.

[0056] The inorganic carrier was prepared as follows: spherical magnesium hydroxide was added to a 0.1 mol / L cerium nitrate ethanol solution at a dosage ratio of 15 g / L. After mixing and stirring for 30 min, a 0.05 mol / L hexamethylenetetramine solution was added dropwise while stirring. The resulting dispersion was then heated to 80 °C and stirred at a rate of 1200 r / min for 5 h. After the reaction was completed, the product components were filtered. The filter cake was washed four times alternately with deionized water and anhydrous ethanol and then vacuum dried to obtain the inorganic carrier. The molar ratio of cerium nitrate to hexamethylenetetramine in the dispersion was 1:5.

[0057] The preparation method of spherical magnesium hydroxide includes the following steps:

[0058] Step 1: Add 0.4 times the volume of glycerol and 0.5 times the volume of sodium citrate aqueous solution to a 5 mol / L magnesium sulfate aqueous solution. Then, while stirring, add sodium hydroxide aqueous solution dropwise. Stop adding alkali when a white precipitate forms, and continue stirring until the white precipitate disappears. Store the resulting first mixed component for later use. The concentration of the sodium citrate aqueous solution is 0.06 mol / L, and the concentration of the sodium hydroxide aqueous solution is 0.02 mol / L. The dropping rate is 15 drops / min, and the stirring speed is 150 r / min.

[0059] Step 2: Seal 28wt% ammonia water with perforated plastic wrap and place it together with an equal volume of the first mixed component in a sealed container. Keep the mixture at 45℃ for 50 hours. After the reaction is complete, perform solid-liquid separation on the product components. Wash the filter cake 8 times with deionized water. Test the washing liquid with a barium ion solution until no white precipitate is formed. Then wash it 5 times with anhydrous ethanol. After washing, dry the filter cake to obtain spherical magnesium hydroxide.

[0060] Comparative Example 1: The main difference between this comparative example and Example 1 is that an equal amount of inorganic carrier is used to replace the functional microparticles in this comparative example.

[0061] Comparative Example 2: The main difference between this comparative example and Example 1 is that an equal amount of spherical magnesium hydroxide is used instead of functional microparticles in this comparative example.

[0062] Comparative Example 3: The main difference between this comparative example and Example 1 is that no grafting agent was used in the preparation of functional microparticles in this comparative example.

[0063] Comparative Example 4: The main difference between this comparative example and Example 1 is that ammonium polyphosphate was not used in the preparation of functional microparticles in this comparative example.

[0064] Performance testing

[0065] The polyethylene flame-retardant masterbatches produced in Examples 1-3 and Comparative Examples 1-4 were respectively mixed with high-density polyethylene (same as in Example 1), zinc borate, pentaerythritol stearate, nano titanium dioxide, and antioxidant 1076 in a high-speed mixer at a mass ratio of 1:20:0.5:0.8:0.6:0.3, and then the mixture was made into polyethylene films. The relevant properties of the polyethylene films prepared in Examples 1-3 and Comparative Examples 1-4 were then tested as follows:

[0066] 1. Vertical flammability rating: Tested according to GB / T 2408 test standard.

[0067] 2. Limiting Oxygen Index: Tested according to GB / T 2406 test standard.

[0068] 3. Thermo-oxidative aging test: The test shall be conducted in accordance with the GB / T 2951 test standard.

[0069] 4. Ultraviolet Aging Test: The polyethylene film samples in each group were subjected to an ultraviolet light intensity of 300 W / m². 2 The aging process was carried out at an aging temperature of 60℃ for 168 hours.

[0070] 5. Tensile strength retention rate and elongation at break retention rate: Each group of polyethylene film samples was cut into strips 15cm long and 1.5cm wide. Tensile testing was performed using a tensile testing machine (model CMT6104, Mester Industrial Systems Co., Ltd.) at an initial length of 50mm and a tensile speed of 350mm / min. The initial tensile strength and initial elongation at break were recorded after fracture. After thermo-oxidative aging tests, each polyethylene film sample was tested using the same method. Tensile strength retention rate = (thermal-oxidative tensile strength / initial tensile strength) × 100%; Elongation at break retention rate = (thermal-oxidative elongation at break / initial elongation at break) × 100%.

[0071] The obtained test data is recorded in the table below:

[0072]

[0073] By comparing and analyzing the relevant data in the table, it can be seen that the polyethylene flame-retardant masterbatch produced by this invention can not only effectively enhance the flame-retardant properties of polyethylene products, but also effectively improve their anti-aging properties. While ensuring the quality of polyethylene products, it also extends their service life to a certain extent. This indicates that the polyethylene flame-retardant masterbatch and its production process provided by this invention have a broader market prospect and are more suitable for promotion.

[0074] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A polyethylene flame-retardant masterbatch, characterized in that, It is composed of the following raw materials in parts by weight: 50-60 parts polyethylene, 10-20 parts hydroxymethylphosphonic acid, 15-20 parts HDPE-g-MAH, 0.8-1.5 parts initiator, 1-2 parts antioxidant and 3-6 parts functional microparticles.

2. The polyethylene flame-retardant masterbatch according to claim 1, characterized in that: The polyethylene used is high-density polyethylene, and its melt index at 190℃ and 2.16kg is 7-20g / 10min.

3. The polyethylene flame-retardant masterbatch according to claim 1, characterized in that: The initiator is selected from any one of dicumyl peroxide, benzoyl peroxide, and tert-butyl peroxide.

4. The polyethylene flame-retardant masterbatch according to claim 1, characterized in that: The antioxidant is selected from any one of antioxidant 1010, antioxidant 168, and antioxidant DSTP.

5. The polyethylene flame-retardant masterbatch according to claim 1, characterized in that, The method for preparing the functional microparticles includes the following steps: Step 1: Add 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid to oxalyl chloride at a solid-liquid ratio of 20-30 g / L. Reflux the reaction until no irritating gas is released, then terminate the reaction. Remove excess oxalyl chloride from the product components under reduced pressure. The remaining components are referred to as grafting agents. Step 2: Disperse the pretreated inorganic carrier in a mixed solvent consisting of equal volumes of ethanol and N,N-dimethylformamide at a dosage ratio of 20-50 g / L. Then add grafting agent at a mass ratio of 0.5-0.6 times that of the pretreated inorganic carrier and ammonium polyphosphate at a mass ratio of 0.3-0.5 times. Stir until homogeneous, then add benzopyridine at a mass ratio of 2-4 times that of the grafting agent. After homogeneous dispersion, stir and react under nitrogen protection for 20-25 hours. After the reaction is complete, filter the product components. Wash the filter cake alternately with ethanol and N,N-dimethylformamide 3-4 times and then vacuum dry to obtain functional microparticles.

6. The polyethylene flame-retardant masterbatch according to claim 5, characterized in that, The preparation method of the pretreated inorganic carrier is as follows: the inorganic carrier is uniformly dispersed in toluene at a solid-liquid ratio of 10-30 g / L, 3-aminopropyltrimethoxysilane (5-8% by volume of toluene) is added, and after mixing and stirring evenly, triethylamine (0.2-0.3 times the volume of 3-aminopropyltrimethoxysilane) is added, and the reaction is carried out at 70-85°C for 10-15 h. After the reaction is completed, the product components are filtered, washed and vacuum dried in sequence to obtain the pretreated inorganic carrier.

7. The polyethylene flame-retardant masterbatch according to claim 6, characterized in that, The inorganic carrier is prepared as follows: spherical magnesium hydroxide is added to an ethanol solution of 0.05–0.1 mol / L cerium nitrate at a dosage ratio of 5–15 g / L. After mixing and stirring for 20–30 min, a 0.02–0.05 mol / L hexamethylenetetramine solution is added dropwise while stirring. The resulting dispersion is then heated to 70–80 °C and stirred at a rate of 800–1200 r / min for 3–5 h. After the reaction is complete, the product components are filtered. The filter cake is washed alternately with deionized water and anhydrous ethanol 3–4 times and then vacuum dried to obtain the inorganic carrier. The molar ratio of cerium nitrate to hexamethylenetetramine in the dispersion is 1:3–5.

8. The polyethylene flame-retardant masterbatch according to claim 7, characterized in that, The method for preparing the spherical magnesium hydroxide includes the following steps: Step 1: Add 0.2-0.4 times the volume of glycerol and 0.3-0.5 times the volume of sodium citrate aqueous solution to a 2-5 mol / L magnesium sulfate aqueous solution. Then, while stirring, add sodium hydroxide aqueous solution dropwise. Stop adding alkali when a white precipitate forms, and continue stirring until the white precipitate disappears. Store the resulting first mixed component for later use. The concentration of the sodium citrate aqueous solution is 0.04-0.06 mol / L. Step 2: Seal 25-28 wt% ammonia water with perforated plastic wrap and place it together with an equal volume of the first mixed component in a sealed container. Keep the mixture at 35-45°C for 40-50 hours. After the reaction is complete, perform solid-liquid separation on the product components. Wash the filter cake with deionized water 5-8 times. Test the washing liquid with a barium ion solution until no white precipitate is formed. Then wash it with anhydrous ethanol 3-5 times. After washing, dry the filter cake to obtain spherical magnesium hydroxide.

9. A polyethylene flame-retardant masterbatch according to claim 8, characterized in that: The concentration of the sodium hydroxide aqueous solution is 0.01–0.02 mol / L, the dropping rate is 10–15 drops / min, and the stirring rate is 100–150 r / min.

10. A production process for polyethylene flame-retardant masterbatch according to any one of claims 1 to 9, characterized in that, The process includes the following steps: accurately weighing all the raw materials required for preparing polyethylene flame retardant masterbatch, mixing and stirring the raw materials evenly, feeding them into a twin-screw extruder, and extruding and granulating them at a temperature of 170-185°C to obtain polyethylene flame retardant masterbatch.

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