Flame-retardant high-toughness HDPE (high-density polyethylene) resin and preparation method thereof

Abstract

The invention relates to the technical field of HDPE resin, and discloses flame-retardant high-toughness HDPE resin and a preparation method thereof.The flame-retardant high-toughness HDPE resin is prepared through the steps that phosphonitrilic chloride trimer, 4, 5-diamino-o-diphenyl nitrile, hydrazine hydrate and the like serve as raw materials, an intermediate 2 is obtained through a reaction, amino in the intermediate 2 and vanillic aldehyde are subjected to condensation to obtain vanillic aldehyde cyclotriphosphazene, and the vanillic aldehyde cyclotriphosphazene is subjected to flame retardant modification to obtain the flame-retardant high-toughness HDPE resin. The flame-retardant and high-toughness HDPE resin is prepared by the following steps: by taking 3-isocyanate propyl triethoxy silane as a bonding arm, reacting with an intermediate 2 and attapulgite to obtain attapulgite-based cyclotriphosphazene, and finally adding vanillin cyclotriphosphazene and the attapulgite-based cyclotriphosphazene into HDPE (High-Density Polyethylene) to melt, blend and press, thereby obtaining the flame-retardant and high-toughness HDPE resin. The HDPE resin prepared by the invention has excellent flame retardant property, heat resistance and mechanical property.

Description

Technical Field

[0001] The invention relates to the technical field of HDPE resins, in particular to a flame retardant high-toughness HDPE resin and a preparation method thereof. Background Art

[0002] High-density polyethylene (HDPE) is one of the general-purpose plastics with the largest market demand and the most extensive application prospects in the polymer field. It is widely used in pipes, wires and cables, plastics and other fields due to its good mechanical properties, dielectric properties, chemical resistance, etc. With the continuous improvement of the economy, the requirements and standards for HDPE are getting higher and higher. Traditional HDPE resin can no longer meet the needs of modern society. Therefore, it is necessary to improve the comprehensive performance of HDPE to meet the needs of modern society.

[0003] Hexachlorocyclotriphosphazene is a type of organic compound with a six-membered ring skeleton consisting of alternating phosphorus and nitrogen double bonds and connected to active chlorine. It is widely used in flame retardant materials, medical materials and other fields. Attapulgite, also known as palygorskite, is a hydrated magnesium aluminum silicate with a needle-like three-dimensional structure. It is widely used in industrial building materials, food processing, environmental protection and other fields.

[0004] For example, the patent with authorization announcement number CN 109251397 B discloses a high-strength HDPE corrugated pipe material and a preparation method thereof. The invention uses high-density polyethylene, attapulgite, etc. as raw materials, and the prepared HDPE has good flame retardant properties and strength, but does not improve the heat resistance of the material. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a flame retardant high-toughness HDPE resin and a preparation method thereof. The prepared HDPE resin has excellent flame retardancy, toughness and heat resistance.

[0006] (II) Technical solution A flame retardant high-toughness HDPE resin, comprising the following components: 100 parts of high-density polyethylene, 5-15 parts of vanillin-based cyclotriphosphazene, and 5-15 parts of attapulgite-based cyclotriphosphazene; The preparation method of the flame retardant high-toughness HDPE resin is: The high-density polyethylene, vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene are uniformly mixed and added into a 180°C internal mixer for melt blending, and then placed in a 180°C, 10MPa flat plate vulcanizer for pressing for 2-5 minutes, and then cold pressed for 4-8 minutes to obtain a flame-retardant high-toughness HDPE resin; The preparation method of the vanillinyl cyclotriphosphazene is as follows: (1) Under nitrogen protection, hexachlorocyclotriphosphazene and 4,5-diamino-o-dibenzonitrile were added to a flask, and then toluene solvent was added. Triethylamine was added to the solution while stirring, and the temperature was raised to 100-110°C. The reaction was stirred at a constant temperature for 10-15 hours. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1. The reaction route is: ; (2) Add intermediate 1 and ethanol solvent to a flask, stir and disperse, then add hydrazine hydrate, heat to 70-80°C, react for 1-3 hours, and after the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2. The reaction route is: ; (3) Add vanillin and ethanol solvent into a flask, stir and disperse, heat to 50-60°C, add intermediate 2, stir and react for 6-12 hours, and after the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene. The reaction route is: ; More preferably, in (1), the usage ratio of hexachlorocyclotriphosphazene to 4,5-diamino-o-diphenylnitrile is 1 g: (1.4-1.8) g: (0.5-0.8) g.

[0007] Further preferably, in said (2), the usage ratio of the intermediate 1 to hydrazine hydrate is 1 g:(0.085-0.1) g.

[0008] More preferably, in (3), the usage ratio of vanillin to intermediate 2 is (1.4-1.6) g:1 g.

[0009] Preferably, the preparation method of the attapulgite-based cyclotriphosphazene is as follows: under nitrogen protection, the intermediate 2 is added to a flask, and then pyridine and 3-isocyanatepropyltriethoxysilane are added thereto, and the reaction is stirred at 65-80° C. for 1.5-3 hours. After the reaction is completed, it is cooled to room temperature, and then attapulgite is added thereto, and the temperature is raised to 70-80° C., and the reaction is continued for 10-16 hours. After the reaction is completed, it is cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene. The reaction route is: ; Further preferably, the usage ratio of the intermediate 2,3-isocyanatepropyltriethoxysilane and attapulgite is 1 g: (0.25-0.4) mL: (0.8-1) g.

[0010] 3. Beneficial technical effects The invention uses hexachlorocyclotriphosphazene and 4,5-diamino-o-dibenzonitrile to undergo a substitution reaction under the catalytic reaction of triethylamine to obtain an intermediate 1, and under the catalytic reduction of hydrazine hydrate, the cyano group in the intermediate 1 is reduced to an amino group to obtain an intermediate 2, and the amino group in the intermediate 2 is condensed with vanillin to obtain vanillin-based cyclotriphosphazene, and 3-isocyanate propyltriethoxysilane is used as a bonding arm to react with the intermediate 2 and attapulgite to obtain attapulgite-based cyclotriphosphazene, and finally, vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene are added to HDPE for melt blending and pressing to obtain a flame-retardant high-toughness HDPE resin.

[0011] The flame-retardant high-toughness HDPE resin prepared by the present invention contains phosphorus element. In the condensed phase, high-valent phosphorus will turn into a large amount of phosphoric acid, and then generate polyphosphoric acid. The polyphosphoric acid has the function of coating the surface of the substrate and promoting the dehydration and carbonization of the substrate, and the dense carbon layer formed can isolate gas exchange. In the gas phase, low-valent phosphorus can form phosphorus-containing free radicals, react with H· and OH· in the air that promote combustion, quench the free radicals, dilute the combustible gas, and terminate the combustion. The nitrogen element contained therein can generate nitrogen, nitrogen dioxide and other flame-retardant gases when heated, dilute the content of flammable gas in the air, and the phosphorus-nitrogen synergistic system further improves the flame retardant performance of the HDPE resin.

[0012] The flame-retardant high-toughness HDPE resin prepared by the present invention contains a Schiff base structure, and the C=N functional group in its molecular structure can undergo a self-crosslinking reaction under high temperature conditions to form a polybenzoxazine with a stable structure and a six-membered ring structure in which C and N elements are alternately bonded. During the combustion process, a stable carbon layer can be formed, giving the material excellent carbon-forming performance, and can improve the thermal stability of the HDPE resin and assist in improving the flame retardant performance of the resin material. In addition, the relatively large amount of benzene ring rigid structure and attapulgite contained therein further improve the thermal stability of the material.

[0013] The HDPE resin prepared by the present invention contains attapulgite, which is easy to agglomerate. Therefore, the dispersion degree of unmodified attapulgite in HDPE resin is not good. The present invention combines it with organic matter to increase the dispersion degree of attapulgite in the matrix resin, and the organically modified attapulgite can be used as a stress concentration point. When the resin is impacted, the attapulgite can debond with the matrix to produce holes and form cavities, and transfer the received energy to the surrounding matrix, causing it to undergo severe plastic deformation and dissipate energy, thereby improving the toughness of the resin. In addition, the vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene prepared by the present invention contain more branched structures, which can produce more cross-linking sites with the matrix resin. When impacted, the impact energy can be dispersed to other molecular chains along the cross-linked network structure, further improving the toughness of the resin material. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a photo of the cone calorimeter residual sample of comparative example 2; Figure 2 This is a photo of the cone calorimetry residual sample of Example 1. DETAILED DESCRIPTION

[0015] The present invention is combined with specific embodiments to further illustrate the technical scheme of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the claims attached to the application.

[0016] Example 1 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 14.14 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 8.08 g of triethylamine was added to the solution while stirring. The temperature was raised to 105°C and stirred at constant temperature for 15 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0017] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.5 g of hydrazine hydrate, heat to 75 °C, react for 2 h. After the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0018] (3) Add 32 g of vanillin and 150 mL of ethanol solvent into a flask, stir and disperse, heat to 55°C, add 20.9 g of intermediate 2, stir and react for 12 h. After the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene.

[0019] (4) Under nitrogen protection, 10 g of intermediate 2 was added to a flask, and then 100 mL of dry pyridine and 3 mL of 3-isocyanatepropyltriethoxysilane were added thereto. The mixture was stirred at 65 °C for 3 h. After the reaction was completed, the mixture was cooled to room temperature. Then 8 g of attapulgite was added thereto, the mixture was stirred and mixed evenly, the temperature was raised to 75 °C, and the reaction was continued for 16 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene.

[0020] (5) 100 g of HDPE, 5 g of vanillin-based cyclotriphosphazene, and 5 g of attapulgite-based cyclotriphosphazene were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat-plate vulcanizer at 180 °C and 10 MPa for pressing for 5 min, and then cold-pressed for 6 min to obtain a flame-retardant and high-toughness HDPE resin.

[0021] Example 2 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 15.8 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 5.05 g of triethylamine was added to the solution while stirring. The temperature was raised to 110°C and stirred at constant temperature for 10 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0022] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.3 g of hydrazine hydrate, heat to 75°C, react for 3 h. After the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0023] (3) Add 30 g of vanillin and 150 mL of ethanol solvent into a flask, stir and disperse, heat to 55°C, add 20.9 g of intermediate 2, stir and react for 10 h. After the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene.

[0024] (4) Under nitrogen protection, 10 g of intermediate 2 was added to a flask, and then 100 mL of dry pyridine and 2.5 mL of 3-isocyanatepropyltriethoxysilane were added thereto. The mixture was stirred at 70 °C for 2 h. After the reaction was completed, the mixture was cooled to room temperature. Then 10 g of attapulgite was added thereto, the mixture was stirred and mixed evenly, the temperature was raised to 70 °C, and the reaction was continued for 15 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene.

[0025] (5) 100 g of HDPE, 7.5 g of vanillin-based cyclotriphosphazene, and 7.5 g of attapulgite-based cyclotriphosphazene were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat-plate vulcanizer at 180 °C and 10 MPa for pressing for 2 min, and then cold-pressed for 8 min to obtain a flame-retardant and high-toughness HDPE resin.

[0026] Example 3 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 18.18 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 6.06 g of triethylamine was added to the solution while stirring. The temperature was raised to 100 °C and stirred at a constant temperature for 15 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0027] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.28 g of hydrazine hydrate, heat to 80°C, react for 2 h, and after the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0028] (3) 33.44 g of vanillin and 150 mL of ethanol solvent were added to a flask, stirred and dispersed, and heated to 55° C. 20.9 g of intermediate 2 was added thereto, and stirred to react for 6 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain vanillin-based cyclotriphosphazene.

[0029] (4) Under nitrogen protection, 10 g of intermediate 2 was added to a flask, and then 100 mL of dry pyridine and 4 mL of 3-isocyanatepropyltriethoxysilane were added thereto. The mixture was stirred at 80 °C for 1.5 h. After the reaction was completed, the mixture was cooled to room temperature. Then 8 g of attapulgite was added thereto, the mixture was stirred and mixed evenly, the temperature was raised to 80 °C, and the reaction was continued for 10 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene.

[0030] (5) 100 g of HDPE, 10 g of vanillin-based cyclotriphosphazene, and 10 g of attapulgite-based cyclotriphosphazene were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat-plate vulcanizer at 180 °C and 10 MPa for pressing for 5 min, and then cold-pressed for 4 min to obtain a flame-retardant and high-toughness HDPE resin.

[0031] Example 4 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 15 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 8.08 g of triethylamine was added to the solution while stirring. The temperature was raised to 105°C and stirred at constant temperature for 15 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0032] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.4 g of hydrazine hydrate, heat to 70°C, react for 3 h, and after the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0033] (3) Add 29.26 g of vanillin and 150 mL of ethanol solvent into a flask, stir and disperse, heat to 60°C, add 20.9 g of intermediate 2, stir and react for 10 h. After the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene.

[0034] (4) Under nitrogen protection, 10 g of intermediate 2 was added to a flask, and then 100 mL of dry pyridine and 3 mL of 3-isocyanatepropyltriethoxysilane were added thereto. The mixture was stirred at 70 °C for 2 h. After the reaction was completed, the mixture was cooled to room temperature. Then 9 g of attapulgite was added thereto, the mixture was stirred and mixed evenly, the temperature was raised to 75 °C, and the reaction was continued for 14 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene.

[0035] (5) 100 g of HDPE, 12.5 g of vanillin-based cyclotriphosphazene, and 12.5 g of attapulgite-based cyclotriphosphazene were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat vulcanizer at 180 °C and 10 MPa for 3 min, and then cold-pressed for 6 min to obtain a flame-retardant and high-toughness HDPE resin.

[0036] Example 5 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 16 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 6 g of triethylamine was added to the solution while stirring. The temperature was raised to 105°C and stirred at a constant temperature for 15 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0037] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.5 g of hydrazine hydrate, heat to 75°C, react for 1 h. After the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0038] (3) 30.4 g of vanillin and 150 mL of ethanol solvent were added to a flask, stirred and dispersed, and heated to 50°C. 20.9 g of intermediate 2 was added thereto, and the mixture was stirred and reacted for 12 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain vanillin-based cyclotriphosphazene.

[0039] (4) Under nitrogen protection, 10 g of intermediate 2 was added to a flask, and then 100 mL of dry pyridine and 3 mL of 3-isocyanatepropyltriethoxysilane were added thereto. The mixture was stirred at 70 °C for 2 h. After the reaction was completed, the mixture was cooled to room temperature. Then 9 g of attapulgite was added thereto, the mixture was stirred and mixed evenly, the temperature was raised to 75 °C, and the reaction was continued for 12 h. After the reaction was completed, the mixture was cooled to room temperature, washed with deionized water, and dried to obtain attapulgite-based cyclotriphosphazene.

[0040] (5) 100 g of HDPE, 15 g of vanillin-based cyclotriphosphazene, and 15 g of attapulgite-based cyclotriphosphazene were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat-plate vulcanizer at 180 °C and 10 MPa for pressing for 5 min, and then cold-pressed for 5 min to obtain a flame-retardant and high-toughness HDPE resin.

[0041] Comparative Example 1 (1) Under nitrogen protection, 10.1 g of hexachlorocyclotriphosphazene and 14.14 g of 4,5-diamino-o-dibenzonitrile were added to a flask, and then 200 mL of toluene solvent was added. 8.08 g of triethylamine was added to the solution while stirring. The temperature was raised to 105°C and stirred at constant temperature for 15 h. After the reaction was completed, the solution was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1.

[0042] (2) Add 15 g of intermediate 1 and 150 mL of ethanol solvent into a flask, stir and disperse, then add 1.5 g of hydrazine hydrate, heat to 75 °C, react for 2 h. After the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2.

[0043] (3) Add 32 g of vanillin and 150 mL of ethanol solvent into a flask, stir and disperse, heat to 55°C, add 20.9 g of intermediate 2, stir and react for 12 h. After the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene.

[0044] (4) 100 g of HDPE, 5 g of vanillin-based cyclotriphosphazene, and 5 g of attapulgite were mixed evenly and added to an internal mixer at 180 °C for melt blending. The mixture was then placed in a flat vulcanizer at 180 °C and 10 MPa for 5 min, and then cold-pressed for 6 min to obtain a flame-retardant and high-toughness HDPE resin.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that step (5) does not contain vanillin-based cyclotriphosphazene and attapulgite.

[0046] Refer to ASTM D2863-2019 and use LOI tester to test the flame retardant properties of materials; Refer to ASTM D3801-2019 and use a horizontal vertical combustion apparatus to test the flame retardant properties of the material.

[0047] Table 1: LOI (%) UL-94 Example 1 28.1 V-0 Example 2 29.4 V-0 Example 3 31.3 V-0 Example 4 32.0 V-0 Example 5 32.9 V-0 Comparative Example 1 26.8 V-1 Comparative Example 2 17.1 No level It can be seen from the table that the HDPE resin prepared by the present invention has good flame retardant properties.

[0048] The total heat release and the maximum heat release rate were tested using a cone calorimeter with a heat radiation flux of 50 kW / m 2 .

[0049] Table 2: Maximum heat release rate (kW / m2) Total heat release (MJ / m2) Example 1 356 74.0 Example 2 302 66.3 Example 3 228 59.1 Example 4 186 54.2 Example 5 164 48.4 Comparative Example 1 408 98.4 Comparative Example 2 895 115.0 It can be seen from the table that the total heat release and the maximum heat release rate of HDPE resin gradually decrease with the increase of vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene. Therefore, adding vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene can effectively improve the flame retardant properties of HDPE resin.

[0050] Use a cantilever pendulum impact tester to test the notched impact strength of the material; Use a universal material testing machine to test the tensile properties of the material.

[0051] Table 3: Notched impact strength (KJ / m2) Tensile strength (MPa) Example 1 67.4 27.2 Example 2 71.2 29,0 Example 3 75.0 30.7 Example 4 76.8 31.4 Example 5 73.1 30.1 Comparative Example 1 58.3 25.4 Comparative Example 2 27.1 21.9 The higher the notched impact strength, the better the toughness. It can be seen from the table that the HDPE resin prepared by the present invention has good tensile properties and toughness.

[0052] The thermal stability was tested using a thermogravimetric analyzer in a nitrogen atmosphere with a heating rate of 10°C / min and a temperature range of 25-650°C.

[0053] Table 4: Carbon residue rate (℃) Example 1 15.68 Example 2 16.23 Example 3 16.89 Example 4 17.35 Example 5 17.62 Comparative Example 1 12.38 Comparative Example 2 0 As can be seen from the table, the HDFE resin prepared by the present invention has good thermal stability, and the residual carbon rate of the system at 600°C can reach up to 17.62, indicating that the increase of vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene is conducive to the stability and heat resistance of the carbon layer.

[0054] Depend on Figure 1 , Figure 2 It can be seen that the surface of the carbon layer of Comparative Example 2 is discontinuous and has many holes, while the surface of the carbon layer of Example 1 is continuous and dense. This continuous and dense carbon layer can effectively play a role of barrier shielding, delaying the further combustion of the matrix resin, thereby improving the combustion performance of the material.

[0055] The above is only a preferred embodiment of the present invention, and does not limit the technical solution of the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A flame retardant high-toughness HDPE resin, characterized in that: The invention comprises the following components: 100 parts of high-density polyethylene, 5-15 parts of vanillin-based cyclotriphosphazene, and 5-15 parts of attapulgite-based cyclotriphosphazene; The preparation method of the flame retardant high-toughness HDPE resin is: The high-density polyethylene, vanillin-based cyclotriphosphazene and attapulgite-based cyclotriphosphazene are uniformly mixed and added into a 180°C internal mixer for melt blending, and then placed in a 180°C, 10MPa flat plate vulcanizer for pressing for 2-5 minutes, and then cold pressed for 4-8 minutes to obtain a flame-retardant high-toughness HDPE resin; The preparation method of the vanillinyl cyclotriphosphazene is as follows: (1) Under nitrogen protection, hexachlorocyclotriphosphazene and 4,5-diamino-o-dibenzonitrile were added to a flask, and then toluene solvent was added. Triethylamine was added to the solution while stirring, and the temperature was raised to 100-110°C. The mixture was stirred at a constant temperature for 10-15 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered under reduced pressure, washed with deionized water, and dried to obtain intermediate 1; (2) Add intermediate 1 and ethanol solvent into a flask, stir and disperse, then add hydrazine hydrate, heat to 70-80°C, react for 1-3 hours, and after the reaction is completed, cool to room temperature, filter, concentrate, wash with ethanol, and dry to obtain intermediate 2; (3) Add vanillin and ethanol solvent into a flask, stir and disperse, heat to 50-60°C, add intermediate 2, stir and react for 6-12 hours. After the reaction is completed, cool to room temperature, wash with deionized water, and dry to obtain vanillin-based cyclotriphosphazene.

2. The flame retardant high-toughness HDPE resin according to claim 1, characterized in that: In the above (1), the usage ratio of hexachlorocyclotriphosphazene and 4,5-diamino-o-diphenylnitrile is 1 g: (1.4-1.8) g: (0.5-0.8) g.

3. The flame retardant high-toughness HDPE resin according to claim 1, characterized in that: In the above (2), the usage ratio of the intermediate 1 and hydrazine hydrate is 1 g: (0.085-0.1) g.

4. The flame retardant high-toughness HDPE resin according to claim 1, characterized in that: In the above (3), the usage ratio of vanillin and intermediate 2 is (1.4-1.6) g:1 g.

5. The flame retardant high-toughness HDPE resin according to claim 1, characterized in that: The preparation method of the attapulgite-based cyclotriphosphazene is as follows: under nitrogen protection, the intermediate 2 is added into a flask, and then pyridine and 3-isocyanatepropyltriethoxysilane are added thereto, and the reaction is stirred at 65-80° C. for 1.5-3 hours. After the reaction is completed, the reaction is cooled to room temperature, and then attapulgite is added thereto, and the temperature is raised to 70-80° C. and the reaction is continued for 10-16 hours. After the reaction is completed, the reaction is cooled to room temperature, and the attapulgite-based cyclotriphosphazene is washed with deionized water and dried to obtain the attapulgite-based cyclotriphosphazene.

6. The flame retardant high-toughness HDPE resin according to claim 5, characterized in that: The usage ratio of the intermediate 2,3-isocyanatepropyltriethoxysilane and attapulgite is 1g: (0.25-0.4)mL: (0.8-1)g.

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