Preparation method of antistatic flame-retardant polyethylene material

Abstract

The invention relates to the technical field of polyethylene, and discloses a preparation method of an antistatic flame-retardant polyethylene material, which comprises the following steps: adding 100 parts by weight of polyethylene resin, 15-30 parts by weight of sodium sulfonate-based flame retardant and 0.8-1.5 parts by weight of compatilizer into a mixer for mixing, and then carrying out melt mixing, extrusion and pelletizing in a twin-screw extruder to obtain the antistatic flame-retardant polyethylene material. The antistatic flame-retardant polyethylene material is obtained. The sodium sulfonate-based flame retardant provided by the invention contains phosphate, nitrogen and sulfonate groups to form a nitrogen-phosphorus-sulfur flame retardant, so that the limit oxygen index and flame retardance of the polyethylene material are improved. The flame retardant contains a large number of hydrophilic sulfonate groups, can improve the hydrophilicity of the surface of polyethylene and improve the antistatic performance, contains terminal hydroxyl groups, can react with compatilizers such as maleic anhydride grafted polyethylene, and has little influence on the mechanical properties of polyethylene materials.

Description

Technical Field

[0001] The present invention relates to the technical field of polyethylene, and specifically to a preparation method of an antistatic and flame-retardant polyethylene material. Background Art

[0002] Due to its good low-temperature resistance, acid and alkali resistance, water resistance, and easy processing and molding properties, polyethylene is widely used in packaging, wire and cable, building materials, automotive parts, etc. However, the limiting oxygen index of polyethylene is relatively low, only about 18%, resulting in poor flame retardancy and easy combustion. In addition, the resistivity of polyethylene is relatively large and the antistatic performance is poor, which limits the actual application fields of polyethylene.

[0003] Generally, adding flame retardants and antistatic agents to polyethylene can improve the flame retardancy, antistatic and other properties of the material, such as flame retardants like ammonium polyphosphate, guanidine sulfamate, decabromodiphenyl ether, etc.; antistatic agents like sodium dodecylbenzenesulfonate, sodium benzenesulfonate, tetradecylmethyldihydroxyethylammonium bromide, etc. Chinese Patent CN113248793B discloses a halogen-free flame retardant-antistatic-stabilizer composition and a halogen-free flame retardant-antistatic polyethylene composite material and its preparation method. Using surface-modified piperazine pyrophosphate polymers, etc. as flame retardants and sodium polystyrenesulfonate, quaternary amine carboxylate inner salt copolymers, etc. as antistatic agents can improve the flame retardancy, antistatic, wear resistance and other properties of polyethylene materials. However, this patent requires the additional addition of phosphorus-containing promoters such as ammonium polyphosphate, melamine, and polyphosphoric acid to effectively improve the flame retardancy of the material. Summary of the Invention

[0004] The present invention solves the problems of poor flame retardancy and antistatic performance of polyethylene materials.

[0005] Technical Solution: A preparation method of an antistatic and flame-retardant polyethylene material:

[0006] (1) Add diphenylamine (CAS No. 122-39-4) and potassium tert-butoxide to acetonitrile, stir, then add 3-chloro-1,2-propanediol (CAS No. 96-24-2). After reaction, rotary evaporate, wash with deionized water, and purify the product by recrystallization with ethanol to obtain diphenylamino-1,2-propanediol. The preparation reaction formula is:

[0007]

[0008] (2) Add 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide (CAS No. 714-87-4), diphenylamino-1,2-propanediol, and triethylamine to acetonitrile, heat to the reaction temperature, stir and react, then rotary evaporate, wash with water and acetonitrile, and dry to obtain a flame retardant precursor.

[0009] (3) Add the flame retardant precursor to concentrated sulfuric acid, heat to the reaction temperature, stir the reaction, then pour the solution into ice water, filter, wash successively with a sodium hydroxide solution with a mass fraction of 10 - 15% and deionized water, and dry to obtain the sulfonate-based flame retardant. The preparation reaction formula is:

[0010]

[0011] (4) Add 100 parts by weight of polyethylene resin, 15 - 30 parts by weight of the sulfonate-based flame retardant, 0.8 - 1.5 parts by weight of compatibilizer, and 0.3 - 0.5 parts by weight of antioxidant to a mixer, and mix at 80 - 100 °C for 10 - 20 min; then melt and mix in a twin-screw extruder, with the temperature in zones 1 - 6 being 140 - 180 °C, the screw speed being 30 - 50 r / min, extrude, and pelletize to obtain the antistatic flame-retardant polyethylene material.

[0012] Preferably, in (1), the ratio of diphenylamine, potassium tert-butoxide, and 3-chloro-1,2-propanediol is 1 mol:(1.4 - 1.6) mol:(1.6 - 2) mol.

[0013] Preferably, in (1), the reaction temperature is 20 - 30 °C and the reaction time is 12 - 18 h.

[0014] Preferably, in (2), the ratio of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, diphenylamino-1,2-propanediol, and triethylamine is 1 mol:(1.04 - 1.1) mol:(2 - 2.1) mol.

[0015] Preferably, in (2), the reaction temperature is 80 - 85 °C and the reaction time is 18 - 24 h.

[0016] Preferably, in (3), the ratio of the flame retardant precursor to concentrated sulfuric acid is 1 g:(80 - 120) mL.

[0017] Preferably, in (4), the reaction temperature is 80 - 90 °C and the reaction time is 1 - 1.5 h.

[0018] Preferably, in (5), the compatibilizer is maleic anhydride-grafted polyethylene or maleic anhydride-grafted polyethylene wax.

[0019] Beneficial technical effects: In the present invention, diphenylamino-1,2-propanediol containing nitrogen element and benzene ring is polymerized with 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide to obtain a flame retardant precursor with terminal hydroxyl groups. Then, the benzene ring is sulfonated with concentrated sulfuric acid to introduce a large number of sodium sulfonate groups in the side chain, obtaining a sodium sulfonate-based flame retardant. The sodium sulfonate-based flame retardant is blended and pelletized with compatibilizers such as polyethylene resin and maleic anhydride grafted polyethylene to obtain an antistatic and flame retardant polyethylene material. The flame retardant contains phosphate esters, nitrogen elements and sulfonate groups, forming a nitrogen-phosphorus-sulfur flame retardant. When burning, substances such as phosphoric acid are generated, which promotes the dehydration and carbonization of the polyethylene resin matrix. At the same time, incombustible gases such as nitrogen oxides and sulfur oxides are generated, which can dilute the oxygen concentration, thereby improving the limiting oxygen index and flame retardant performance of the polyethylene material.

[0020] The sodium sulfonate-based flame retardant of the present invention contains a large number of hydrophilic sodium sulfonate groups, which can improve the hydrophilicity of the polyethylene surface, cause the polyethylene surface to adsorb water molecules in the air to form a conductive film layer, thereby reducing the surface resistivity and improving the antistatic performance of the material.

[0021] The sodium sulfonate-based flame retardant of the present invention contains terminal hydroxyl groups, which can react with compatibilizers such as maleic anhydride grafted polyethylene, so that there is good compatibility between the sodium sulfonate-based flame retardant and the polyethylene resin matrix. After adding the flame retardant, the influence on the tensile strength and elongation at break of the polyethylene material is very small, and the material maintains good mechanical properties. Specific embodiments

[0022] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0023] The following polyethylene resin, model DFDA7042, Shanghai Sutong Industrial Co., Ltd. Maleic anhydride grafted polyethylene, model EMX110D, Dongguan Sujia Polymer Raw Material Co., Ltd. Maleic anhydride grafted polyethylene wax, model Clariant MA4351, Shanghai Dianchuang Industrial Co., Ltd.

[0024] Example 1:

[0025] (1) Add 60 mmol of diphenylamine and 96 mmol of potassium tert-butoxide to 700 mL of acetonitrile, stir for 10 min, add 96 mmol of 3-chloro-1,2-propanediol, stir and react at 20 °C for 18 h, rotary evaporate, wash with deionized water, and purify the product by recrystallization with ethanol to obtain diphenylamino-1,2-propanediol.

[0026] (2) Add 100 mmol of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, 106 mmol of diphenylamino-1,2-propanediol, and 200 mmol of triethylamine to 200 mL of acetonitrile, heat to 80 °C, stir and reflux for 24 h, rotary evaporate, wash with water and acetonitrile, and dry to obtain a flame retardant precursor.

[0027] (3) Add 40 g of the flame retardant precursor to 3.2 L of concentrated sulfuric acid, heat to 90 °C, stir and react for 1 h, pour the solution into ice water after stirring, filter, wash successively with 15% sodium hydroxide solution by mass and deionized water, and dry to obtain a sulfonate-based flame retardant.

[0028] (4) Add 1 kg of polyethylene resin, 150 g of sulfonate-based flame retardant, 8 g of compatibilizer maleic anhydride-grafted polyethylene, and 4 g of antioxidant 1010 to a mixer, mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder, the temperatures of zones 1-6 are 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, 175 °C, the screw speed is 50 r / min, extrude, and pelletize to obtain an antistatic and flame retardant polyethylene material.

[0029] Comparative Example 1:

[0030] (1) Add 1 kg of polyethylene resin, 8 g of compatibilizer maleic anhydride-grafted polyethylene, and 4 g of antioxidant 1010 to a mixer, mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder, the temperatures of zones 1-6 are 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, 175 °C, the screw speed is 50 r / min, extrude, and pelletize to obtain a polyethylene material.

[0031] Comparative Example 2:

[0032] (1) Add 1 kg of polyethylene resin, 150 g of flame retardant precursor, 8 g of compatibilizer maleic anhydride-grafted polyethylene, and 4 g of antioxidant 1010 to a mixer, mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder, the temperatures of zones 1-6 are 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, 175 °C, the screw speed is 50 r / min, extrude, and pelletize to obtain a polyethylene material.

[0033] Comparative Example 3:

[0034] (1) Add 1 kg of polyethylene resin, 150 g of sulfonate-based flame retardant (prepared in Example 1), and 4 g of antioxidant 1010 to a mixer, and mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder, with the temperatures in zones 1-6 being 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, and 175 °C, the screw speed being 50 r / min, extrude, and pelletize to obtain a polyethylene material.

[0035] Comparative Example 4:

[0036] (1) Add 100 mmol of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, 106 mmol of hydroquinone, and 200 mmol of triethylamine to 200 mL of acetonitrile, heat to 80 °C, stir and reflux for 24 h, rotary evaporate, wash with water and acetonitrile, and dry to obtain a flame retardant precursor.

[0037] (2) Add 40 g of the flame retardant precursor to 3.2 L of concentrated sulfuric acid, heat to 90 °C, stir for 1 h, pour the solution into ice water after stirring, filter, wash successively with a 15% sodium hydroxide solution by mass and deionized water, and dry to obtain a sulfonate-based flame retardant.

[0038] (3) Add 1 kg of polyethylene resin, 150 g of sulfonate-based flame retardant, 8 g of compatibilizer maleic anhydride-grafted polyethylene, and 4 g of antioxidant 1010 to a mixer, and mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder, with the temperatures in zones 1-6 being 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, and 175 °C, the screw speed being 50 r / min, extrude, and pelletize to obtain an antistatic and flame-retardant polyethylene material.

[0039] Example 2:

[0040] (1) Add 60 mmol of diphenylamine and 84 mmol of potassium tert-butoxide to 800 mL of acetonitrile, stir for 20 min, add 120 mmol of 3-chloro-1,2-propanediol, stir and react at 30 °C for 12 h, rotary evaporate, wash with deionized water, and purify the product by recrystallization with ethanol to obtain diphenylamino-1,2-propanediol.

[0041] (2) Add 100 mmol of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, 110 mmol of diphenylamino-1,2-propanediol, and 200 mmol of triethylamine to 250 mL of acetonitrile. Heat to 85 °C, stir, and reflux for 18 h. Rotate and evaporate, wash with water and acetonitrile, and dry to obtain the flame retardant precursor.

[0042] (3) Add 40 g of the flame retardant precursor to 4.8 L of concentrated sulfuric acid. Heat to 85 °C and stir for 1 h. After stirring, pour the solution into ice water, filter, wash successively with a 15% sodium hydroxide solution by mass and deionized water, and dry to obtain the sodium sulfonate-based flame retardant.

[0043] (4) Add 1 kg of polyethylene resin, 200 g of the sodium sulfonate-based flame retardant, 10 g of the compatibilizer maleic anhydride-grafted polyethylene wax, and 3 g of antioxidant 1010 to a mixer and mix at 100 °C for 10 min; then melt and mix in a twin-screw extruder. The temperatures of zones 1-6 are 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, and 175 °C, the screw speed is 50 r / min, extrude, and pelletize to obtain the antistatic and flame retardant polyethylene material.

[0044] Example 3:

[0045] (1) Add 100 mmol of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, 110 mmol of diphenylamino-1,2-propanediol (prepared in Example 1), and 210 mmol of triethylamine to 250 mL of acetonitrile. Heat to 80 °C, stir, and reflux for 24 h. Rotate and evaporate, wash with water and acetonitrile, and dry to obtain the flame retardant precursor.

[0046] (2) Add 40 g of the flame retardant precursor to 4 L of concentrated sulfuric acid. Heat to 80 °C and stir for 1.5 h. After stirring, pour the solution into ice water, filter, wash successively with a 15% sodium hydroxide solution by mass and deionized water, and dry to obtain the sodium sulfonate-based flame retardant.

[0047] (3) Add 1 kg of polyethylene resin, 250 g of the sodium sulfonate-based flame retardant, 12 g of the compatibilizer maleic anhydride-grafted polyethylene wax, and 5 g of antioxidant 1010 to a mixer and mix at 80 °C for 20 min; then melt and mix in a twin-screw extruder. The temperatures of zones 1-6 are 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, and 175 °C, the screw speed is 30 r / min, extrude, and pelletize to obtain the antistatic and flame retardant polyethylene material.

[0048] Example 4:

[0049] (1) Add 100 mmol of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, 104 mmol of diphenylamino-1,2-propanediol, and 200 mmol of triethylamine to 200 mL of acetonitrile. Heat to 80 °C, stir, and reflux for 24 h. Then perform rotary evaporation, wash with water and acetonitrile, and dry to obtain the flame retardant precursor.

[0050] (2) Add 40 g of the flame retardant precursor to 3.2 L of concentrated sulfuric acid. Heat to 90 °C and stir for 1 h. After stirring, pour the solution into ice water, filter, and wash successively with a 15% sodium hydroxide solution by mass and deionized water, and then dry to obtain the sodium sulfonate-based flame retardant.

[0051] (3) Add 1 kg of polyethylene resin, 300 g of the sodium sulfonate-based flame retardant, 15 g of the compatibilizer maleic anhydride grafted polyethylene, and 4 g of antioxidant 1010 to a mixer and mix at 90 °C for 20 min. Then melt and mix in a twin-screw extruder with the temperatures of zones 1-6 being 140 °C, 160 °C, 170 °C, 180 °C, 180 °C, and 175 °C respectively, and the screw speed being 30 r / min. Extrude and pelletize to obtain the antistatic and flame retardant polyethylene material.

[0052] Inject the polyethylene material into a spline using an injection molding machine. Test the oxygen index according to the GB / T 2406.1-2008 standard. Test the surface resistivity according to GB / T 1410-2006. Test the tensile properties according to the GB / T 1040.1-2018 standard.

[0053] Table 1 Performance Test of Polyethylene Material

[0054]

[0055]

[0056] Compared with the polyethylene material of Comparative Example 1, a sodium sulfonate-based flame retardant is added to the polyethylene materials of Examples 1-4. The flame retardant contains phosphate ester, nitrogen element and sulfonate group, forming a nitrogen-phosphorus-sulfur flame retardant. When burning, substances such as phosphoric acid are generated, which promotes the dehydration and carbonization of the polyethylene resin matrix. At the same time, non-combustible gases such as nitrogen oxides and sulfur oxides are generated, which can dilute the oxygen concentration, thereby improving the limiting oxygen index and flame retardant performance of the polyethylene material. And the sodium sulfonate-based flame retardant contains a large number of hydrophilic sulfonate groups, which can improve the hydrophilicity of the polyethylene surface, making the polyethylene surface adsorb water molecules in the air to form a conductive film layer, thereby reducing the surface resistivity and improving the antistatic performance of the material. And the sodium sulfonate-based flame retardant contains terminal hydroxyl groups, which can react with compatibilizers such as maleic anhydride grafted polyethylene, so that there is good compatibility between the sodium sulfonate-based flame retardant and the polyethylene resin matrix. After adding the flame retardant, the influence on the tensile strength and elongation at break of the polyethylene material is very small, and the material maintains good mechanical properties.

[0057] Compared with Example 1, the flame retardant precursor added in Comparative Example 2 does not contain sulfonate groups and does not form a nitrogen-phosphorus-sulfur flame retardant, resulting in a lower limiting oxygen index of the material and a very large surface resistivity and poor antistatic performance. In Comparative Example 3, maleic anhydride grafted polyethylene was not added, resulting in poor compatibility between the flame retardant and the polyethylene resin, and a large decrease in the tensile strength and elongation at break of the material. In Comparative Example 4, using hydroquinone as the raw material, the prepared flame retardant does not contain nitrogen element and does not form a nitrogen-phosphorus-sulfur flame retardant, resulting in a lower limiting oxygen index of the material. And hydroquinone only contains one benzene ring, and there are fewer hydrophilic sodium sulfonate groups on the side chain of the flame retardant after sulfonation reaction, resulting in a larger surface resistivity of the polyethylene material and poor antistatic performance.

Claims

1. A preparation method of an antistatic and flame-retardant polyethylene material, characterized in that, The preparation method is as follows: (1) Add 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, diphenylamino-1,2-propanediol, and triethylamine to acetonitrile, heat to the reaction temperature, stir the reaction, then perform rotary evaporation, washing, and drying to obtain a flame retardant precursor; (2) Add the flame retardant precursor to concentrated sulfuric acid, heat to the reaction temperature, stir the reaction, then pour the solution into ice water, filter, wash with sodium hydroxide solution and deionized water, and dry to obtain a sodium sulfonate-based flame retardant; (3) Add 100 parts by weight of polyethylene resin, 15 - 30 parts by weight of the sodium sulfonate-based flame retardant, 0.8 - 1.5 parts by weight of a compatibilizer, and 0.3 - 0.5 parts by weight of an antioxidant to a mixer for mixing, then perform melt mixing in a twin-screw extruder, extrude, and pelletize to obtain an antistatic and flame retardant polyethylene material.

2. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (1), the ratio of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane 3,9-dioxide, diphenylamino-1,2-propanediol, and triethylamine is 1 mol:(1.04 - 1.1) mol:(2 - 2.1) mol.

3. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (1), the reaction temperature is 80 - 85 °C, and the reaction time is 18 - 24 h.

4. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (2), the ratio of the flame retardant precursor to concentrated sulfuric acid is 1 g:(80 - 120) mL.

5. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (2), the reaction temperature is 80 - 90 °C, and the reaction time is 1 - 1.5 h.

6. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (3), the mixing temperature in the mixer is 80 - 100 °C, and the mixing time is 10 - 20 min; the temperatures of zones 1 - 6 of the twin-screw extruder are 140 - 180 °C, and the screw speed is 30 - 50 r / min.

7. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 1, characterized in that, In the above (3), the compatibilizer is maleic anhydride grafted polyethylene or maleic anhydride grafted polyethylene wax.

8. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 2, characterized in that, The preparation method of diphenylamino-1,2-propanediol in the above (3) is as follows: Add diphenylamine and potassium tert-butoxide to acetonitrile, stir for 10 - 20 min, add 3-chloro-1,2-propanediol, stir and react at 20 - 30 °C for 12 - 18 h, perform rotary evaporation, washing, and purification by recrystallization to obtain diphenylamino-1,2-propanediol.

9. The preparation method of the antistatic and flame-retardant polyethylene material according to claim 8, characterized in that, In the above (3), the ratio of diphenylamine, potassium tert-butoxide, and 3-chloro-1,2-propanediol is 1 mol:(1.4 - 1.6) mol:(1.6 - 2) mol.

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