Corrosion resistant polyethylene pipe material and method of manufacture

Abstract

The present application relates to the technical field of polyethylene, and discloses an anti-corrosion polyethylene pipeline material and a preparation method, wherein triazine charring agent and silver-loaded zirconium phosphate antibacterial agent are added into a high-speed mixer, dispersed, polyethylene resin, nylon 6 resin, ammonium polyphosphate, triazine charring agent and antioxidant are added, mixed, and the mixture is melt-blended, extruded and granulated in a double-screw extruder to obtain the anti-corrosion polyethylene pipeline material. The triazine charring agent and the ammonium polyphosphate form an intumescent flame-retardant system, improving the limiting oxygen index and the flame-retardant performance of the pipeline material. The amide bond contained in the triazine charring agent forms interaction with the surface of the silver-loaded zirconium phosphate antibacterial agent during the dispersion process, realizing the dispersion of the silver-loaded zirconium phosphate antibacterial agent, being conducive to reducing the agglomeration of the antibacterial agent, improving the dispersibility of the antibacterial agent in the polyethylene / nylon 6 pipeline material, increasing the antibacterial and mildew-resistant sites, and improving the antibacterial, mildew-resistant and microbial corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of polyethylene technology, specifically to a corrosion-resistant polyethylene pipe material and its preparation method. Background Technology

[0002] Pipeline materials mainly include polyethylene, polyvinyl chloride, and nylon. Polyethylene has advantages such as good flexibility, smooth inner wall, high wear resistance, and strong acid and alkali resistance, while nylon has advantages such as high mechanical strength and strong high-temperature resistance. They are widely used in gas transmission, oilfield gathering pipelines, mine ventilation, and agricultural irrigation. However, both polyethylene and nylon are flammable, making them unsuitable for the needs of petrochemical, mining, and other fields. Currently, flame retardants are mainly used to improve the flame retardant properties of polyethylene and nylon, such as phosphorus-based and nitrogen-based halogen-free flame retardants. These have good compatibility with the polymer resin matrix, require only small amounts, and exhibit good flame retardant performance. Patent CN114685881B discloses a flame-retardant LLDPE / EVA composite material, its preparation method, and its application. This material mixes linear low-density polyethylene, ethylene-vinyl acetate copolymer, phosphate-based halogen-free flame retardants, nylon resin, and other synergistic additives to prepare a composite material with good flame retardant properties. However, the poor compatibility between nylon resin and polyethylene can affect the mechanical properties of polyethylene.

[0003] When polyethylene, nylon, and other pipes are used in water supply and drainage, agricultural irrigation, and other fields, they are prone to bacterial and mold growth, and are susceptible to microbial corrosion, which can affect the performance of the pipes and pose health and safety hazards. Silver-based antibacterial agents, typically using zirconium phosphate, zeolite, etc., as carriers, have advantages such as being non-toxic and environmentally friendly, having good biocompatibility, and excellent antibacterial and antifungal properties, and are widely used. In order to improve the aggregation of silver-based antibacterial agents and enhance their dispersibility in polymer materials such as polyethylene, dispersion modification of silver-based antibacterial agents is required. Dispersants mainly include oleamide, titanate coupling agents, and silane coupling agents. Summary of the Invention

[0004] The technical problem solved by this invention is to address the issue of low flame retardancy and resistance to microbial corrosion in polyethylene.

[0005] The technical solution of the present invention is: a corrosion-resistant polyethylene pipe material, comprising 70-85 parts by weight of polyethylene resin, 15-30 parts by weight of nylon 6 resin, 20-30 parts by weight of ammonium polyphosphate, 8-15 parts by weight of triazine charring agent, 0.8-2 parts by weight of silver-loaded zirconium phosphate antibacterial agent, and 0.2-0.3 parts by weight of antioxidant.

[0006] The preparation method of corrosion-resistant polyethylene pipe material is as follows: (1) Place the flask in an ice-water bath, add tetrahydrofuran, cyanuric chloride in a ratio of 1 mol:1 mol:(2-2.2) mol, glycine hydrochloride, and diisopropylethylamine, stir the reaction, evaporate the solution by rotary evaporation, and separate the crude product by silica gel column chromatography to obtain 2-(4,6-dichloro-1,3,5-triazine-2-amino)acetamide, the reaction formula is: .

[0007] (2) Add acetone and 2-(4,6-dichloro-1,3,5-triazine-2-amino)acetamide to a flask, stir, then add diaminoalkane monomer and an aqueous solution of sodium carbonate, stir to react, filter, wash the precipitate with water and acetone, and dry to obtain a triazine charring agent. The reaction formula is: .

[0008] (3) Add triazine charring agent and silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer for dispersion, then add polyethylene resin, nylon 6 resin, ammonium polyphosphate, triazine charring agent and antioxidant for mixing, and melt-blend, extrude and granulate the mixture in a twin-screw extruder to obtain corrosion-resistant polyethylene pipe material.

[0009] Furthermore, in (1), the ratio of cyanuric chloride, glycine hydrochloride, and diisopropylethylamine is 1 mol: 1 mol: (2-2.2) mol.

[0010] Furthermore, the reaction time in (1) is 1.5-2h.

[0011] Furthermore, in (2), the ratio of 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide, diaminoalkane monomer, and sodium carbonate is 1 mol: (1-1.1) mol: (2-2.4) mol.

[0012] Furthermore, the structural formula of the diaminoalkane monomer in (2) is NH2-(CH2). n -NH2, a is 12-16.

[0013] Furthermore, in (2), the reaction temperature is 20-40℃ and the reaction time is 12-18h.

[0014] Furthermore, in (3), the temperature of the high-speed mixer during dispersion is 40-70℃, and the dispersion time is 1-2h.

[0015] Furthermore, in (3), the mixing temperature is 90-100℃ and the time is 7-10min.

[0016] Furthermore, in (3), the temperature of each zone of the twin-screw extruder is 150-225℃, and the screw speed is 30-50r / min.

[0017] The beneficial technical effects of this invention are as follows: Using polyethylene and nylon 6 as the matrix of the pipe material, triazine charring agent, ammonium polyphosphate, silver-loaded zirconium phosphate antibacterial agent, etc., are added and blended to obtain an anti-corrosion pipe material. The triazine charring agent contains triazine rings and a large amount of nitrogen element. When burned, it produces nitrogen and other gases, which can dilute oxygen and form an intumescent flame-retardant system with ammonium polyphosphate, thereby improving the limiting oxygen index and flame-retardant performance of the pipe material.

[0018] The triazine charring agent of the present invention has a main molecular chain containing a long carbon chain similar to that of polyethylene, and a side chain containing amide bonds, which form hydrogen bonds with the amide bonds of nylon. This allows the triazine charring agent to compatibilize polyethylene and nylon resin, improve their compatibility, and give the pipe material better tensile strength and mechanical properties.

[0019] The amide bonds contained in the triazine charring agent of the present invention interact with the surface of the silver-loaded zirconium phosphate antibacterial agent during the dispersion process, thereby achieving a dispersing effect on the silver-loaded zirconium phosphate antibacterial agent, playing a good dispersant role, which helps to reduce the aggregation of antibacterial agents, improve their dispersibility in polyethylene / nylon 6 pipe materials, increase antibacterial and antifungal sites, and improve antibacterial, antifungal and antimicrobial corrosion resistance. Detailed Implementation

[0020] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0021] The following polyethylene resin models are listed: Qilu 2100TN00 (Zibo Aole Plastics); Nylon 6 resin model PA6NP2400 (Ningbo Rongsu New Materials); and silver-loaded zirconium phosphate antibacterial agent with a silver content of 2% (Wuhan Linsheng Technology).

[0022] Example 1: (1) Place the flask in an ice-water bath, add 2.9 L of tetrahydrofuran, 0.35 mol of cyanuric chloride, 0.35 mol of glycine hydrochloride, and 0.77 mol of diisopropylethylamine, stir and react for 1.5 h, evaporate the solution by rotary evaporation, and separate the crude product by silica gel column chromatography to obtain 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide.

[0023] (2) Add 500 mL of acetone and 0.25 mol of 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide to a flask, stir, add 0.25 mol of 1,12-diaminododecane and 150 mL of an aqueous solution containing 0.5 mol of sodium carbonate, stir and react at 30 °C for 12 h, filter, wash the precipitate with water and acetone, dry, and obtain the triazine charring agent.

[0024] (3) Add 0.2g of triazine charring agent and 8g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 60℃ for 1h. Then add 850g of polyethylene resin, 150g of nylon 6 resin, 300g of ammonium polyphosphate, 79.8g of triazine charring agent and 3g of antioxidant 1076 and mix at 100℃ for 7min. Melt-blend the mixture in a twin-screw extruder with temperatures of 150℃, 180℃, 210℃, 225℃ and 225℃ in each zone and a screw speed of 30r / min. Extrude and granulate to obtain corrosion-resistant polyethylene pipe material.

[0025] Example 2: (1) Place the flask in an ice-water bath, add 3.2 L of tetrahydrofuran, 0.4 mol of cyanuric chloride, 0.4 mol of glycine hydrochloride and 0.8 mol of diisopropylethylamine, stir and react for 2 h, evaporate the solution by rotary evaporation, and separate the crude product by silica gel column chromatography to obtain 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide.

[0026] (2) Add 600 mL of acetone and 0.3 mol of 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide to a flask, stir, add 0.33 mol of 1,12-diaminododecane and 200 mL of an aqueous solution containing 0.6 mol of sodium carbonate, stir and react at 20 °C for 18 h, filter, wash the precipitate with water and acetone, dry, and obtain the triazine charring agent.

[0027] (3) Add 0.3g of triazine charring agent and 13g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 40°C for 2 hours. Then add 800g of polyethylene resin, 200g of nylon 6 resin, 260g of ammonium polyphosphate, 109.7g of triazine charring agent and 2.6g of antioxidant 1076 and mix at 100°C for 8 minutes. Melt-blend the mixture in a twin-screw extruder with temperatures of 150°C, 180°C, 210°C, 225°C and 225°C in each zone and a screw speed of 30r / min. Extrude and granulate to obtain corrosion-resistant polyethylene pipe material.

[0028] Example 3: (1) Place the flask in an ice-water bath, add 4.5 L of tetrahydrofuran, 0.6 mol of cyanuric chloride, 0.6 mol of glycine hydrochloride, and 1.32 mol of diisopropylethylamine, stir and react for 2 h, evaporate the solution by rotary evaporation, and separate the crude product by silica gel column chromatography to obtain 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide.

[0029] (2) Add 800 mL of acetone and 0.45 mol of 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide to a flask, stir, add 0.45 mol of 1,12-diaminododecane and 300 mL of an aqueous solution containing 1.08 mol of sodium carbonate, stir and react at 40 °C for 12 h, filter, wash the precipitate with water and acetone, dry, and obtain the triazine charring agent.

[0030] (3) Add 0.5g of triazine charring agent and 20g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 70°C for 1h. Then add 700g of polyethylene resin, 300g of nylon 6 resin, 200g of ammonium polyphosphate, 149.5g of triazine charring agent and 2g of antioxidant 1076 and mix at 90°C for 10min. Melt-blend the mixture in a twin-screw extruder with temperatures of 150°C, 180°C, 210°C, 225°C and 225°C in each zone and a screw speed of 50r / min. Extrude and granulate to obtain corrosion-resistant polyethylene pipe material.

[0031] Comparative Example 1 differs from Example 1 in that no triazine charring agent is added.

[0032] (1) Add 8g of silver-loaded zirconium phosphate antibacterial agent, 850g of polyethylene resin, 150g of nylon 6 resin, 300g of ammonium polyphosphate and 3g of antioxidant 1076 to a high-speed mixer and mix at 100°C for 7 minutes. Then melt-blend the mixture in a twin-screw extruder at temperatures of 150°C, 180°C, 210°C, 225°C and 225°C, with the screw speed at 30r / min. Extrude and granulate to obtain polyethylene pipe material.

[0033] Comparative Example 2 differs from Example 1 in that ethylamine hydrochloride is used instead of glycine hydrochloride.

[0034] (1) Place the flask in an ice-water bath, add 2.9 L of tetrahydrofuran, 0.35 mol of cyanuric chloride, 0.35 mol of ethylamine hydrochloride, and 0.77 mol of diisopropylethylamine, stir and react for 1.5 h, then evaporate the solution by rotary evaporation. Separate the crude product by silica gel column chromatography to obtain 4,6-dichloro-2-ethylamino-1,3,5-triazine, with the structural formula: .

[0035] (2) Add 500 mL of acetone and 0.25 mol of 4,6-dichloro-2-ethylamino-1,3,5-triazine to a flask, stir, add 0.25 mol of 1,12-diaminododecane and 150 mL of an aqueous solution containing 0.5 mol of sodium carbonate, stir and react at 30 °C for 12 h, filter, wash the precipitate with water and acetone, dry, and obtain the triazine charring agent.

[0036] (3) Add 0.2g of triazine charring agent and 8g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 60°C for 1h. Then add 850g of polyethylene resin, 150g of nylon 6 resin, 300g of ammonium polyphosphate, 79.8g of triazine charring agent and 3g of antioxidant 1076 and mix at 100°C for 7min. Melt-blend the mixture in a twin-screw extruder with temperatures of 150°C, 180°C, 210°C, 225°C and 225°C in each zone and a screw speed of 30r / min. Extrude and granulate to obtain polyethylene pipe material.

[0037] Comparative Example 3 differs from Example 1 in that ethylenediamine is used instead of 1,12-diaminododecane.

[0038] (1) Add 500 mL of acetone and 0.25 mol of 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide to a flask, stir, add 0.25 mol of ethylenediamine and 150 mL of an aqueous solution containing 0.5 mol of sodium carbonate, stir and react at 30 °C for 12 h, filter, wash the precipitate with water and acetone, dry, and obtain the triazine charring agent.

[0039] (2) Add 0.2g of triazine charring agent and 8g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 60°C for 1h. Then add 850g of polyethylene resin, 150g of nylon 6 resin, 300g of ammonium polyphosphate, 79.8g of triazine charring agent and 3g of antioxidant 1076 and mix at 100°C for 7min. Melt-blend the mixture in a twin-screw extruder with temperatures of 150°C, 180°C, 210°C, 225°C and 225°C in each zone and a screw speed of 30r / min. Extrude and granulate to obtain corrosion-resistant polyethylene pipe material.

[0040] Comparative Example 4 differs from Example 1 in that oleamide is used instead of triazine charring agent.

[0041] (1) Add 0.2g of oleamide and 8g of silver-loaded zirconium phosphate antibacterial agent to a high-speed mixer and disperse at 60°C for 1h. Then add 850g of polyethylene resin, 150g of nylon 6 resin, 300g of ammonium polyphosphate, 79.8g of oleamide and 3g of antioxidant 1076 and mix at 100°C for 7min. Melt-blend the mixture in a twin-screw extruder with temperatures of 150°C, 180°C, 210°C, 225°C and 225°C in each zone and a screw speed of 30r / min. Extrude and granulate to obtain polyethylene pipe material.

[0042] Polyethylene pipe material was injection molded into sample strips, with the temperatures of each section of the injection molding machine being 230℃, 235℃, and 230℃.

[0043] The antibacterial properties of the test strips were tested according to the QB / T 2591-2003 standard, with Escherichia coli as the test species. The antibacterial rate R = (BC) / B × 100%, where C is the average number of recovered bacteria (cfu / tablet) of the antibacterial plastic sample, and B is the average number of recovered bacteria (cfu / tablet) of the blank control sample. Polyethylene pipe material without silver-loaded zirconium phosphate antibacterial agent was used as the blank control sample.

[0044] The anti-mildew performance was tested according to GB / T 24128-2018 standard, and the test strain was Aspergillus niger.

[0045] Tensile properties were tested according to GB / T 1040.1-2025 standard.

[0046] Flame retardant performance was tested according to GB / T 2406.1-2008 standard.

[0047] Table 1 Properties of Polyethylene Pipe Materials Examples 1-3 use polyethylene and nylon 6 as the matrix of the pipe material, exhibiting high antibacterial rate, a mildew resistance rating of 0, excellent resistance to microbial corrosion, and significantly higher tensile strength and limiting oxygen index than Comparative Example 1. It also demonstrates superior mechanical and flame-retardant properties, primarily due to the addition of a triazine charring agent. This agent contains a triazine ring and a large amount of nitrogen, which, upon combustion, produces nitrogen and other gases that dilute oxygen. It forms an intumescent flame-retardant system with ammonium polyphosphate, increasing the limiting oxygen index and improving the flame-retardant performance of the pipe material. Furthermore, the triazine charring agent's main molecular chain contains long carbon chains similar to those of polyethylene, while its side chains contain amide bonds. These bonds form hydrogen bonds with the amide bonds of nylon, allowing the triazine charring agent to compatibilize polyethylene and nylon resins, improving their compatibility and resulting in better mechanical properties and increased tensile strength in the pipe material. The amide bonds contained in the triazine charring agent interact with the surface of the silver-loaded zirconium phosphate antibacterial agent during the dispersion process, thereby achieving a dispersing effect on the silver-loaded zirconium phosphate antibacterial agent. This acts as a good dispersant, which helps reduce the aggregation of the antibacterial agent, improves its dispersibility in polyethylene / nylon 6 pipe materials, increases antibacterial and antifungal sites, enhances antibacterial and antifungal properties, and improves resistance to microbial corrosion.

[0048] The triazine charring agent in Comparative Example 2 does not contain amide bonds, making it difficult to compatibilize polyethylene and nylon resins and improve their compatibility. This results in the tensile strength of the polyethylene / nylon 6 pipe material being lower than that in Example 1. Since the triazine charring agent does not contain amide bonds, it also cannot form an interaction with the surface of the silver-loaded zirconium phosphate antibacterial agent and cannot play a dispersing role. The silver-loaded zirconium phosphate antibacterial agent has poor dispersibility in the polyethylene / nylon 6 pipe material and is prone to agglomeration, resulting in a lower antibacterial rate and mildew resistance.

[0049] The triazine charring agent in Comparative Example 3 does not contain long carbon chains, making it difficult to compatibilize polyethylene and nylon resins and thus failing to improve their compatibility. This results in the tensile strength of the polyethylene / nylon 6 pipe material being significantly lower than that in Example 1.

[0050] Comparative Example 4 used oleamide as a dispersant for silver-loaded zirconium phosphate antibacterial agent. However, as a small molecule compound, it had a poor compatibilizing effect on polyethylene and nylon 6, resulting in the tensile strength of the polyethylene / nylon 6 pipe material being lower than that in Example 1. Furthermore, oleamide does not contain a triazine ring, and excessive addition severely reduced the limiting oxygen index of the pipe material, leading to poor flame retardant performance.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A corrosion-resistant polyethylene pipe material, characterized in that, The corrosion-resistant polyethylene pipe material comprises 70-85 parts by weight of polyethylene resin, 15-30 parts by weight of nylon 6 resin, 20-30 parts by weight of ammonium polyphosphate, 8-15 parts by weight of triazine charring agent, 0.8-2 parts by weight of silver-loaded zirconium phosphate antibacterial agent, and 0.2-0.3 parts by weight of antioxidant. The triazine charring agent is prepared by the following method: acetone and 2-(4,6-dichloro-1,3,5-triazine-2-amino)acetamide are added to a flask, stirred, and then diaminoalkane monomer and an aqueous solution of sodium carbonate are added. The mixture is stirred to react, filtered, the precipitate is washed, and dried to obtain the triazine charring agent.

2. The corrosion-resistant polyethylene pipe material according to claim 1, characterized in that, The ratio of 2-(4,6-dichloro-1,3,5-triazine-2-amino)acetamide, diaminoalkane monomer, and sodium carbonate is 1 mol: (1-1.1) mol: (2-2.4) mol.

3. The corrosion-resistant polyethylene pipe material according to claim 1, characterized in that, The structural formula of the diaminoalkane monomer is NH2-(CH2). n -NH2, a is 12-16.

4. The corrosion-resistant polyethylene pipe material according to claim 1, characterized in that, The reaction temperature is 20-40℃, and the reaction time is 12-18h.

5. The corrosion-resistant polyethylene pipe material according to claim 1, characterized in that, The 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide was prepared by the following method: a flask was placed in an ice-water bath, and tetrahydrofuran, cyanuric chloride, glycine hydrochloride, and diisopropylethylamine were added in a ratio of 1 mol:1 mol:(2-2.2) mol. The mixture was stirred and reacted for 1.5-2 h. The solution was then evaporated by rotary evaporation, and the crude product was separated by silica gel column chromatography to obtain 2-(4,6-dichloro-1,3,5-triazine-2-amino)-acetamide.

6. A method for preparing the corrosion-resistant polyethylene pipe material as described in any one of claims 1-5, characterized in that, The preparation method is as follows: triazine charring agent and silver-loaded zirconium phosphate antibacterial agent are added to a high-speed mixer for dispersion, and then polyethylene resin, nylon 6 resin, ammonium polyphosphate, triazine charring agent and antioxidant are added for mixing. The mixture is then melt-blended, extruded and granulated in a twin-screw extruder to obtain corrosion-resistant polyethylene pipe material.

7. The method for preparing the corrosion-resistant polyethylene pipe material according to claim 6, characterized in that, The temperature of the high-speed mixer during dispersion is 40-70℃, and the dispersion time is 1-2 hours.

8. The method for preparing the corrosion-resistant polyethylene pipe material according to claim 6, characterized in that, The mixing temperature is 90-100℃ and the time is 7-10 minutes.

9. The method for preparing the corrosion-resistant polyethylene pipe material according to claim 6, characterized in that, The temperature of each zone of the twin-screw extruder is 150-225℃, and the screw speed is 30-50 r / min.

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