Polyethylene material for 3PE corrosion prevention and preparation method and application thereof

Abstract

The present application relates to a kind of 3PE anticorrosion polyethylene material and its preparation method and application, the 3PE anticorrosion polyethylene material includes the following components according to weight parts: linear low density polyethylene 55-65 weight parts, random copolymer polypropylene 25-35 weight parts, polyvinyl chloride 5-15 weight parts, toughening agent 3-13 weight parts.The 3PE anticorrosion polyethylene material provided in the present application, by the design of its component, so that the low temperature impact strength of 3PE anticorrosion polyethylene material is high, environmental stress cracking resistance is good, freeze-thaw cycle ability is good, and still has good toughness at low temperature, no brittle damage, meet the application requirements in high-cold area.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a 3PE anti-corrosion polyethylene material, its preparation method, and its application. Background Technology

[0002] Currently, the external corrosion protection layer for oil and gas pipelines both domestically and internationally generally adopts a three-layer polyethylene (3PE) structure, which consists of a fusion-bonded epoxy powder (FBE) underlayer, a polyethylene adhesive intermediate layer, and a polyethylene (PE) outer layer. The polyethylene outer layer typically requires good mechanical strength to withstand mechanical damage during transportation and construction, playing a crucial role in external protection within the three-layer polyethylene structure.

[0003] With the development of oil and gas pipelines such as the West-to-East Gas Pipeline and the my country-Russia natural gas pipeline, winter construction in high-latitude, high-altitude, and frigid regions, including permafrost areas, is inevitable. For example, in Mohe City, Daxinganling region of Heilongjiang Province, the average monthly temperature in winter is usually between -20℃ and -30℃, with some extreme low temperatures reaching around -50℃. In recent years, during pipeline construction in high-altitude and frigid regions, the outer layer of ordinary polyethylene has been frequently subjected to impacts or vibrations during construction, leading to brittle fractures and posing challenges to construction. Furthermore, the large diurnal temperature range in high-altitude and frigid regions, often exceeding 20℃ within a single day, means that pipelines in operation undergo a freeze-thaw cycle almost daily. This prolonged freeze-thaw cycle makes the polyethylene outer layer prone to fatigue fracture, and its resistance to environmental stress cracking is relatively poor.

[0004] CN101747552A discloses a polyethylene compound for the outer layer of steel pipes for corrosion protection and its preparation method. The polyethylene compound for the outer layer of steel pipes for corrosion protection is composed of the following raw materials in parts by weight: high-density polyethylene resin: 45-80; linear low-density polyethylene resin: 15-45; antioxidant: 0.3-1; processing aid: 0.5-1.5; functional masterbatch: 1-3; carbon black masterbatch: 3-7. CN103450540A discloses a special polyethylene material for 3PE corrosion protection and its preparation method. The preparation method involves mixing 50-70 parts of hexene-1 copolymer high-density polyethylene pipe-specific resin A with bimodal molecular weight distribution, 30-50 parts of linear low-density polyethylene B, and 5-8 parts of anti-corrosion special carbon black masterbatch C containing a phenolic composite antioxidant system uniformly through a mixer, and then granulating and homogenizing it through an extruder to obtain the special polyethylene material for 3PE corrosion protection. However, existing polyethylene outer layer materials have poor resistance to environmental stress cracking and are prone to brittle fracture. To meet the requirements of low-temperature environments, higher low-temperature impact strength and freeze-thaw cycle requirements have been proposed for polyethylene outer layer materials to ensure good toughness under low-temperature conditions. Therefore, there is an urgent need to develop an ultra-low temperature polyethylene outer layer material suitable for extremely cold regions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a 3PE anti-corrosion polyethylene material, its preparation method, and its application. Through the design of its components, the 3PE anti-corrosion polyethylene material exhibits high low-temperature impact strength, good resistance to environmental stress cracking, and good freeze-thaw cycle capability. Furthermore, it retains good toughness at low temperatures without embrittlement or breakage, thus meeting the application requirements in cold regions.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a 3PE anti-corrosion polyethylene material, wherein the 3PE anti-corrosion polyethylene material comprises the following components by weight:

[0008]

[0009] The 3PE anti-corrosion polyethylene material provided by this invention, through the synergistic compounding of its various components, exhibits excellent low-temperature impact performance and resistance to environmental stress cracking. Among them, random copolymer polypropylene can improve the toughness and impact resistance of the 3PE anti-corrosion polyethylene material, while also improving its processing performance. Polyvinyl chloride can enhance the flexural resistance of the 3PE anti-corrosion polyethylene material, solving the problem of fatigue fracture of the polyethylene outer layer caused by cyclic freeze-thaw cycles in cold regions, thus making it outstanding in terms of resistance to environmental stress cracking.

[0010] The linear low-density polyethylene is 55-65 parts by weight, for example, 55.5 parts by weight, 56 parts by weight, 56.5 parts by weight, 57 parts by weight, 57.5 parts by weight, 58 parts by weight, 58.5 parts by weight, 59 parts by weight, 59.5 parts by weight, 60 parts by weight, 60.5 parts by weight, 61 parts by weight, 61.5 parts by weight, 62 parts by weight, 62.5 parts by weight, 63 parts by weight, 63.5 parts by weight, 64 parts by weight, 64.5 parts by weight, etc.

[0011] The random copolymer polypropylene is 25-35 parts by weight, for example, it can be 25.5 parts by weight, 26 parts by weight, 26.5 parts by weight, 27 parts by weight, 27.5 parts by weight, 28 parts by weight, 28.5 parts by weight, 29 parts by weight, 29.5 parts by weight, 30 parts by weight, 30.5 parts by weight, 31 parts by weight, 31.5 parts by weight, 32 parts by weight, 32.5 parts by weight, 33 parts by weight, 33.5 parts by weight, 34 parts by weight, 34.5 parts by weight, etc.

[0012] The polyvinyl chloride is 5-15 parts by weight, for example, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 14.5 parts by weight, etc.

[0013] The toughening agent is 3-13 parts by weight, for example, it can be 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, etc.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0015] As a preferred technical solution, the linear low-density polyethylene has a weight-average molecular weight of 50,000-200,000, for example, it can be 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, etc.

[0016] Preferably, the mass percentage of ethylene-based structural units in the random copolymer polypropylene is 1-10%, for example, it can be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

[0017] Preferably, the weight-average molecular weight of the random copolymer polypropylene is 100,000-300,000, for example, it can be 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, 200,000, 210,000, 220,000, 230,000, 240,000, 250,000, 260,000, 270,000, 280,000, 290,000, etc.

[0018] Preferably, the mass ratio of linear low-density polyethylene to random copolymer polypropylene in the 3PE anti-corrosion polyethylene material is (1.8-2.2):1, for example, it can be 1.82:1, 1.84:1, 1.86:1, 1.88:1, 1.9:1, 1.92:1, 1.94:1, 1.96:1, 1.98:1, 2:1, 2.02:1, 2.04:1, 2.06:1, 2.08:1, 2.1:1, 2.12:1, 2.14:1, 2.16:1, 2.18:1, etc.

[0019] Preferably, the weight-average molecular weight of the polyvinyl chloride is 60,000-150,000, for example, it can be 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, etc.

[0020] Preferably, the mass ratio of linear low-density polyethylene to polyvinyl chloride in the 3PE anti-corrosion polyethylene material is (4-12):1, for example, it can be 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, etc.

[0021] Preferably, the toughening agent comprises a polyamide toughening agent and / or an ethylene-vinyl acetate copolymer.

[0022] Preferably, the 3PE anti-corrosion polyethylene material further includes an antioxidant.

[0023] Preferably, the antioxidant comprises pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and / or tris(2,4-di-tert-butylphenyl) phosphite.

[0024] Preferably, the antioxidant in the 3PE anti-corrosion polyethylene material is 0.1-1 parts by weight, for example, it can be 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, 0.9 parts by weight, 0.95 parts by weight, etc.

[0025] Preferably, the 3PE anti-corrosion polyethylene material further includes a light stabilizer.

[0026] Preferably, the light stabilizer comprises di(2,2,6,6-tetramethyl-4-piperidine) sebacate and / or bis(2,2,6,6-tetramethyl-4-piperidine) sebacate.

[0027] Preferably, the light stabilizer in the 3PE anti-corrosion polyethylene material is 0.1-1 parts by weight, for example, it can be 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, 0.9 parts by weight, 0.95 parts by weight, etc.

[0028] In a second aspect, the present invention provides a method for preparing a 3PE anti-corrosion polyethylene material as described in the first aspect, the method comprising:

[0029] The 3PE anti-corrosion polyethylene material is obtained by melt blending linear low-density polyethylene, random copolymer polypropylene, polyvinyl chloride and toughening agent and then extruding.

[0030] The preparation process of the 3PE anti-corrosion polyethylene material provided by this invention is simple, safe, environmentally friendly and pollution-free.

[0031] Preferably, the melt-blended material further includes antioxidants and / or light stabilizers.

[0032] Preferably, the melt blending is carried out in a twin-screw extruder.

[0033] Preferably, the temperatures of each section of the twin-screw extruder are as follows: Zone 1: 170-190℃ (e.g., 172℃, 174℃, 176℃, 178℃, 180℃, 182℃, 184℃, 186℃, 188℃, etc.); Zone 2: 190-210℃ (e.g., 192℃, 194℃, 196℃, 198℃, 200℃, 202℃, 204℃, 206℃, 208℃, etc.); Zone 3: 210-230℃ (e.g., 212℃, 2...). 14℃, 216℃, 218℃, 220℃, 222℃, 224℃, 226℃, 228℃, etc.), Zone 4 temperature 210-230℃ (e.g., 212℃, 214℃, 216℃, 218℃, 220℃, 222℃, 224℃, 226℃, 228℃, etc.), Zone 5 temperature 220-240℃ (e.g., 222℃, 224℃, 226℃, 228℃, 230℃, 232℃, 234℃, 236℃, 238℃, etc.).

[0034] Preferably, the extrusion process further includes a pelletizing step.

[0035] Thirdly, the present invention provides a 3PE anti-corrosion material, wherein the 3PE anti-corrosion material includes the 3PE anti-corrosion polyethylene material as described in the first aspect.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The 3PE anti-corrosion polyethylene material provided by this invention possesses excellent low-temperature impact strength and good resistance to environmental stress cracking. Even in extreme low-temperature environments, it still exhibits excellent impact strength and toughness, with a low-temperature impact strength of 80-105 kJ / m. 2 This effectively avoids the problem of cracking of the outer layer of polyethylene during low-temperature construction, while also having good freeze-thaw cycle capability, fully meeting the construction needs of cold regions. Detailed Implementation

[0038] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0039] The sources of some components in the examples and comparative examples are as follows:

[0040] (1) Linear low-density polyethylene: purchased from Sinopec Yangzi Petrochemical Company, LLDPE 7042, with a weight average molecular weight of 50,000-200,000;

[0041] (2) Random copolymer polypropylene: purchased from Beijing Yanhua Petrochemical Co., Ltd. PPR 4220, with a mass percentage of ethylene-based structural units of 1-10% and a weight-average molecular weight of 100,000-300,000.

[0042] (3) Polyvinyl chloride: Purchased from Sinopec Qilu Petrochemical Company PVC QS-1050P, with a weight-average molecular weight of 60,000-150,000;

[0043] (4) Toughening agent: Dow Fusabond N493 toughening agent;

[0044] (5) Antioxidant: Saint-Gobain AT10;

[0045] (6) Light stabilizer: BASF Tinuvin 770DF;

[0046] (7) Homopolymer polypropylene: purchased from Sinopec Zhenhai Refining & Chemical Co., Ltd. PPH-M60, with a weight average molecular weight of 150,000-250,000.

[0047] Example 1

[0048] A 3PE anti-corrosion polyethylene material, wherein the 3PE anti-corrosion polyethylene material comprises the following components by weight: 60 parts by weight of linear low-density polyethylene, 30 parts by weight of random copolymer polypropylene, 10 parts by weight of polyvinyl chloride, 8 parts by weight of toughening agent Fusabond N4938, 0.5 parts by weight of antioxidant AT10, and 0.5 parts by weight of light stabilizer BASF Tinuvin 770DF.

[0049] The preparation method of the 3PE anti-corrosion polyethylene material includes:

[0050] Linear low-density polyethylene, random copolymer polypropylene, polyvinyl chloride, toughening agent Fusabond N493, antioxidant AT10, and light stabilizer BASF Tinuvin 770DF are added to a mixer and stirred until homogeneous. The mixture is then conveyed to the reactor of a twin-screw extruder via a feeder. The temperatures of the five zones in the heating area of ​​the twin-screw extruder are set to 180℃, 200℃, 220℃, 220℃, and 230℃, respectively. Under the heating and compression of the twin-screw extruder, the mixed material undergoes a series of physical and chemical changes, gradually melting into a viscous flow state. Driven by the screw, it flows out through the gaps in the filter screen, die head, and mandrel, entering a cooling water tank for rapid cooling. Then, it is pulled into a pelletizer by a traction device to obtain the 3PE anti-corrosion polyethylene material.

[0051] Example 2

[0052] A 3PE anti-corrosion polyethylene material, wherein the 3PE anti-corrosion polyethylene material comprises the following components by weight: 55 parts by weight of linear low-density polyethylene, 25 parts by weight of random copolymer polypropylene, 5 parts by weight of polyvinyl chloride, 3 parts by weight of toughening agent Fusabond N4933, 0.5 parts by weight of antioxidant AT10, and 0.5 parts by weight of light stabilizer BASF Tinuvin 770DF.

[0053] The preparation method of the 3PE anti-corrosion polyethylene material is the same as in Example 1.

[0054] Example 3

[0055] A 3PE anti-corrosion polyethylene material, wherein the 3PE anti-corrosion polyethylene material comprises the following components by weight: 65 parts by weight of linear low-density polyethylene, 35 parts by weight of random copolymer polypropylene, 15 parts by weight of polyvinyl chloride, 3 parts by weight of toughening agent Fusabond N4931, 0.5 parts by weight of antioxidant AT10, and 0.5 parts by weight of light stabilizer BASF Tinuvin 770DF.

[0056] The preparation method of the 3PE anti-corrosion polyethylene material is the same as in Example 1.

[0057] Example 4

[0058] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 3 is that the mass of the random copolymer polypropylene is 25 parts by weight. All other raw materials, process parameters and steps are the same as in Example 3.

[0059] Example 5

[0060] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 2 is that the mass of the random copolymer polypropylene is 35 parts by weight. All other raw materials, process parameters and steps are the same as in Example 2.

[0061] Example 6

[0062] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 3 is that the mass of polyvinyl chloride is 5 parts by weight, while the other raw materials, process parameters and steps are the same as in Example 3.

[0063] Example 7

[0064] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 2 is that the mass of polyvinyl chloride is 15 parts by weight, while the other raw materials, process parameters and steps are the same as in Example 2.

[0065] Comparative Example 1

[0066] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that polyvinyl chloride is replaced with linear low-density polyethylene and random copolymer polypropylene is replaced with linear low-density polyethylene. All other raw materials, process parameters and steps are the same as in Example 1.

[0067] Comparative Example 2

[0068] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that polyvinyl chloride is replaced by linear low-density polyethylene in equal mass. All other raw materials, process parameters and steps are the same as in Example 1.

[0069] Comparative Example 3

[0070] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that random copolymer polypropylene is replaced with linear low-density polyethylene. All other raw materials, process parameters and steps are the same as in Example 1.

[0071] Comparative Example 4

[0072] A 3PE anti-corrosion polyethylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that random copolymer polypropylene is replaced with homopolymer polypropylene. All other raw materials, process parameters and steps are the same as in Example 1.

[0073] Performance testing

[0074] (1) Low-temperature impact strength: The test was conducted according to GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test". 4mm thick test pieces were prepared from 3PE anti-corrosion polyethylene material. Ten A-type notched specimens, each 80mm long and 10mm wide, were cut from the test pieces using a stamping process. The thickness, width, and remaining notch width of each specimen were measured at the center. The specimens were conditioned at -45℃ for 24 hours. Afterward, the specimens were adjusted to a span of 62mm, the pendulum was raised to the specified height, and the specimens were placed on the test machine support with the punch blade facing the impact center and the notch center located on the impact plane. The pendulum was then released, and the average impact strength of the specimens was calculated.

[0075] (2) Embrittlement Test: The test was conducted according to GB / T 5470-2008 "Determination of Embrittlement Temperature of Plastics by Impact Test". 2mm thick test pieces were prepared from 3PE anti-corrosion polyethylene material. Ten samples, each 20mm long and 2.5mm wide, were cut from the test pieces using a stamping process. The samples were first conditioned in a constant temperature and humidity chamber at 23℃ and 50% relative humidity for 96 hours. Then, the samples were fixed in a fixture as cantilever beams. When the bath temperature dropped to -70℃, the samples were immersed in the heat transfer medium for 3 minutes. A single impact was then performed on the sample using a single swinging punch. Finally, the samples were removed from the fixture, and each sample was checked for breakage. The number of broken samples was recorded, and the breakage rate was calculated using the following formula: Breakage Rate = Number of Broken Samples / 10 × 100%.

[0076] (3) Freeze-thaw cycle test: The test was conducted according to Appendix B of SY / T 7036-2016 "Technical Specification for External Anti-corrosion Coating of Pipelines and Equipment in Oil and Gas Stations". 3PE anti-corrosion polyethylene material was applied to the test pipe section under the production process conditions. Ten 150mm × 75mm anti-corrosion layer specimens were cut from the pipe section. The specimens were subjected to 10 cycles of freeze-thaw cycle testing in the following order: -70℃ freezer for 12 hours, room temperature for 12 hours, 40℃ oven for 12 hours, and room temperature for 12 hours (the above constitutes one cycle). After the cycle test, the specimens were removed, and the appearance of the anti-corrosion layer was observed for peeling or cracking. The number of samples with peeling or cracking of the anti-corrosion layer was recorded, and the breakage rate was calculated according to the following formula: Breakage rate = Number of broken samples / 10 × 100%.

[0077] (4) Environmental stress cracking test: The test was conducted according to GB / T 1842-2008 "Environmental stress cracking test method for polyethylene". 3mm thick test pieces were prepared from 3PE anti-corrosion polyethylene material. Ten specimens, each 38mm long and 13mm wide, were cut from the test pieces using a stamping process. The specimens were first conditioned in a constant temperature and humidity chamber at 23℃ and 50% relative humidity for 72 hours. Then, after scoring and bending, the specimens were placed in test tubes containing 10% nonylphenol polyoxyethylene ether (TX-10) medium. Timing was started from the moment the test tubes were immersed in a 50℃ constant temperature bath. The cracking condition of the specimens was observed periodically according to the specified time. The test duration was 1008 hours. The number of cracked samples was recorded and calculated using the following formula: Crack rate = Number of cracked samples / 10 × 100%.

[0078] The 3PE anti-corrosion polyethylene materials provided in Examples 1-7 and Comparative Examples 1-4 were tested according to the above method. The test results are shown in Table 1 below:

[0079] Table 1

[0080]

[0081] As shown in Table 1, the 3PE anti-corrosion polyethylene material provided by this invention has an impact strength of 80 kJ / m at -45℃. 2 It exhibits excellent low-temperature impact performance, far exceeding the industry's technical requirements for polyethylene materials in cold regions (≥65kJ / m). 2 Meanwhile, the 3PE anti-corrosion polyethylene material provided by this invention still has good toughness at a low temperature of -70℃, and has good resistance to environmental stress cracking and freeze-thaw cycle capability, which can fully meet the application requirements of oil and gas pipeline outer protective layer in cold regions.

[0082] As can be seen from Examples 4-5, the mass ratio of linear low-density polyethylene to random copolymer polypropylene needs to be controlled within a suitable range. If the mass ratio is too small, the impact resistance and low-temperature impact strength of the 3PE anti-corrosion polyethylene material will decrease. If the mass ratio is too large, the environmental stress cracking resistance of the 3PE anti-corrosion polyethylene material will deteriorate.

[0083] As can be seen from Examples 6-7, the mass ratio of linear low-density polyethylene to polyvinyl chloride needs to be controlled within a suitable range. If the mass ratio is too small, the freeze-thaw resistance of the 3PE anti-corrosion polyethylene material will decrease; if the mass ratio is too large, the low-temperature impact performance of the 3PE anti-corrosion polyethylene material will decrease.

[0084] As shown in Comparative Example 1, since the 3PE anti-corrosion polyethylene material does not contain random copolymer polypropylene and polyvinyl chloride, the low-temperature impact strength, environmental stress cracking resistance, and freeze-thaw resistance of the 3PE anti-corrosion polyethylene material are significantly reduced.

[0085] As shown in Comparative Example 2, since 3PE anti-corrosion polyethylene material does not contain polyvinyl chloride, the freeze-thaw resistance of 3PE anti-corrosion polyethylene material is significantly reduced.

[0086] As shown in Comparative Example 3, since the 3PE anti-corrosion polyethylene material does not contain random copolymer polypropylene, the low-temperature impact performance and environmental stress cracking resistance of the 3PE anti-corrosion polyethylene material are significantly reduced.

[0087] As shown in Comparative Example 4, the low-temperature impact performance and environmental stress cracking resistance of 3PE anti-corrosion polyethylene material are significantly reduced after replacing random copolymer polypropylene with homopolymer polypropylene.

[0088] The applicant declares that this invention illustrates the 3PE anti-corrosion polyethylene material, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A 3PE anti-corrosion polyethylene material, characterized in that, The 3PE anti-corrosion polyethylene material comprises the following components by weight:

2. The 3PE anti-corrosion polyethylene material according to claim 1, characterized in that, The linear low-density polyethylene has a weight-average molecular weight of 50,000-200,000. Preferably, the mass percentage of ethylene-based structural units in the random copolymer polypropylene is 1-10%. Preferably, the weight-average molecular weight of the random copolymer polypropylene is 100,000-300,000; Preferably, the mass ratio of linear low-density polyethylene to random copolymer polypropylene in the 3PE anti-corrosion polyethylene material is (1.8-2.2):

1.

3. The 3PE anti-corrosion polyethylene material according to claim 1 or 2, characterized in that, The weight-average molecular weight of the polyvinyl chloride is 60,000-150,000; Preferably, the mass ratio of linear low-density polyethylene to polyvinyl chloride in the 3PE anti-corrosion polyethylene material is (4-12):

1.

4. The 3PE anti-corrosion polyethylene material according to any one of claims 1-3, characterized in that, The toughening agent includes a polyamide toughening agent and / or an ethylene-vinyl acetate copolymer.

5. The 3PE anti-corrosion polyethylene material according to any one of claims 1-4, characterized in that, The 3PE anti-corrosion polyethylene material also includes antioxidants; Preferably, the antioxidant comprises pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and / or tris(2,4-di-tert-butylphenyl) phosphite; Preferably, the antioxidant in the 3PE anti-corrosion polyethylene material is 0.1-1 parts by weight.

6. The 3PE anti-corrosion polyethylene material according to any one of claims 1-5, characterized in that, The 3PE anti-corrosion polyethylene material also includes a light stabilizer; Preferably, the light stabilizer comprises di(2,2,6,6-tetramethyl-4-piperidin) sebacate and / or bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate; Preferably, the light stabilizer in the 3PE anti-corrosion polyethylene material is 0.1-1 parts by weight.

7. A method for preparing a 3PE anti-corrosion polyethylene material as described in any one of claims 1-6, characterized in that, The preparation method includes: The 3PE anti-corrosion polyethylene material is obtained by melt blending linear low-density polyethylene, random copolymer polypropylene, polyvinyl chloride and toughening agent and then extruding.

8. The preparation method according to claim 7, characterized in that, The melt-blended materials also include antioxidants and / or light stabilizers.

9. The preparation method according to claim 7 or 8, characterized in that, The melt blending is carried out in a twin-screw extruder; Preferably, the temperatures of each section of the twin-screw extruder are: Zone 1: 170-190℃, Zone 2: 190-210℃, Zone 3: 210-230℃, Zone 4: 210-230℃, and Zone 5: 220-240℃. Preferably, the extrusion process further includes a pelletizing step.

10. A 3PE anti-corrosion material, characterized in that, The 3PE anti-corrosion material includes the 3PE anti-corrosion polyethylene material as described in any one of claims 1-6.

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