Low-temperature resistant polyethylene, its preparation method, and 3PE anti-corrosion coating

Abstract

This invention relates to the field of polymer materials technology, and in particular to a low-temperature resistant polyethylene, its preparation method, and a 3PE anti-corrosion layer. The low-temperature resistant polyethylene comprises the following components by weight: 50-80 parts PERT resin, 10-40 parts olefin block copolymer, 0-30 parts metallocene linear low-density polyethylene, 1-3 parts UV-resistant filler, and 0.3-1 parts antioxidant. The polyethylene of this invention exhibits good processing performance, and its notched impact strength at -45°C can reach 100 kJ / m². 2 The above-mentioned impact strength at -60℃ can reach up to 95kJ / m. 2 It exhibits excellent low-temperature resistance. The 3PE anti-corrosion layer made of polyethylene according to this invention can reduce the lower limit of the operating temperature of 3PE anti-corrosion pipelines to below -60°C, greatly improving the stability of 3PE anti-corrosion pipelines under low-temperature operation.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a low-temperature resistant polyethylene, its preparation method, and a 3PE anti-corrosion layer. Background Technology

[0002] The 3PE anti-corrosion coating for steel pipes consists of a fusion-bonded epoxy powder base layer, an adhesive intermediate layer, and an outer polyethylene anti-corrosion layer. These three layers are organically combined into a whole, with the bottom epoxy powder layer firmly bonded to the steel pipe substrate. This coating combines the advantages of both fusion-bonded epoxy powder coatings and polyethylene coatings. The fusion-bonded epoxy powder adheres firmly to the metal surface primarily through the interaction of its active groups with activated ions on the steel pipe surface, forming ionic bonds and physical interlocking forces. The adhesive intermediate layer organically combines the bottom fusion-bonded epoxy powder and the outer polyethylene layer, protecting the bottom fusion-bonded epoxy powder from external corrosion. [ .

[0003] With the development of pipelines, more and more pipelines need to be used in cold external environments, with operating temperatures dropping from -30℃ to -50 to -60℃. This necessitates improving the low-temperature resistance of anti-corrosion pipelines. The better the low-temperature resistance of the polyethylene in the pipeline's anti-corrosion layer, the better the stability of the pipeline during transportation and use at low temperatures, thus avoiding the impact of polyethylene embrittlement caused by low temperatures on the anti-corrosion effect. Furthermore, anti-corrosion steel pipes inevitably experience impacts and scratches during use in low-temperature environments, requiring the anti-corrosion polyethylene to possess sufficient toughness at low temperatures to control damage within acceptable limits. Therefore, improving the low-temperature resistance of 3PE anti-corrosion pipelines is urgently needed.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide low-temperature resistant polyethylene, its preparation method, and a 3PE anti-corrosion layer. The polyethylene of this invention has excellent low-temperature resistance, with a notched impact strength of up to 95 kJ / m at -60°C. 2 This allows the operating temperature limit of 3PE anti-corrosion pipes to be lowered to below -60℃, greatly improving the stability of 3PE anti-corrosion pipes under low temperature operation.

[0006] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides low-temperature resistant polyethylene, comprising the following components in parts by weight:

[0007] The mixture consists of 50-80 parts PERT resin, 10-40 parts olefin block copolymer, 0-30 parts metallocene linear low-density polyethylene, 1-3 parts UV-resistant filler, and 0.3-1 parts antioxidant.

[0008] In a specific embodiment of the present invention, the PERT resin includes at least one of PERT type I resin and PERT type II resin.

[0009] In a specific embodiment of the present invention, the PERT resin includes PERT type I resin and PERT type II resin. Further, the mass ratio of the PERT type I resin to the PERT type II resin is 1:(0.5~2).

[0010] In a specific embodiment of the present invention, the olefin block copolymer includes at least one of Infuse 9010, Infuse 9817, Infuse 9107, Infuse 9530, Infuse 9100, Infuse 9507, Infuse 9007, Infuse 9077, Infuse 9000, Infuse 9807 and Infuse 9900.

[0011] In a specific embodiment of the present invention, the mass ratio of the PERT resin to the olefin block copolymer is (1.25~3.5):1.

[0012] In a specific embodiment of the present invention, the density of the metallocene linear low-density polyethylene is 0.91–0.93 g / cm³. 3 At 190℃ / 2.16kg, the melt index is 0.1~4g / 10min.

[0013] In a specific embodiment of the present invention, the melt flow rate of the low-temperature resistant polyethylene at 190℃ / 2.16kg is ≥0.49g / 10min.

[0014] In a specific embodiment of the present invention, the low-temperature resistant polyethylene has a notched impact strength ≥110kJ / m at -45℃. 2 The low-temperature resistant polyethylene has a notched impact strength ≥70kJ / m at -60℃. 2 .

[0015] The second aspect of the present invention provides a method for preparing low-temperature resistant polyethylene according to the first aspect of the present invention, comprising the following steps: mixing and extruding the low-temperature resistant polyethylene according to the composition of the first aspect of the present invention.

[0016] A third aspect of the present invention provides a 3PE anti-corrosion layer, comprising a polyethylene anti-corrosion layer; the polyethylene anti-corrosion layer is mainly made of the low-temperature resistant polyethylene of the first aspect of the present invention.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The polyethylene of the present invention has good processing performance, and its notched impact strength at -45℃ can reach 100kJ / m 2 The above-mentioned notched impact strength at -60℃ can reach up to 95kJ / m. 2 It has excellent low-temperature resistance;

[0019] (2) The 3PE anti-corrosion layer made of polyethylene according to the present invention can reduce the lower limit of the operating temperature of 3PE anti-corrosion pipeline to below -60℃, which greatly improves the stability of 3PE anti-corrosion pipeline under low temperature operation. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0021] With the development of the pipeline industry, higher requirements have been placed on the low-temperature impact resistance of polyethylene materials. For example, the notched impact strength at -60℃ needs to be ≥65kJ / m. 2 Currently, the notched impact strength of ordinary corrosion-resistant polyethylene at -60℃ is far lower than this, only reaching about 10-20 kJ / m. 2 The notch impact strength.

[0022] Existing anti-corrosion polyethylene has two main methods: one uses high-density polyethylene as the main material, combined with metallocene polyethylene and ethylene propylene rubber for toughening, but its low-temperature resistance cannot meet the current requirements for notched impact strength at -60℃; another method uses high-density polyethylene and metallocene polyethylene as the main materials, combined with the introduction of peroxides to cross-link the polyethylene, forming a cross-linked network structure to improve toughness, but this method introduces both antioxidants and peroxides, making the processing difficult to control and resulting in poor stability, and the peroxides consume antioxidants, affecting the material's aging resistance; yet another method uses oil-extended SEBS and SEPS for toughening, which has a certain toughening effect, but oil-extended SEBS and SEPS will seep oil during long-term use, and the oil will migrate to the adhesive and epoxy interface, affecting the bonding strength and thus the service life of the anti-corrosion pipeline.

[0023] Based on this, the first aspect of the present invention provides a low-temperature resistant polyethylene, comprising the following components by weight: 50-80 parts of PERT resin, 10-40 parts of olefin block copolymer, 0-30 parts of metallocene linear low-density polyethylene, 1-3 parts of UV-resistant filler, and 0.3-1 parts of antioxidant.

[0024] PERT resin is a type of polyethylene material with good heat resistance. The inventors of this invention discovered that PERT resin contains numerous long branches, which facilitates entanglement between molecular chains, thereby improving the material's low-temperature impact strength. Its low-temperature impact resistance is superior to that of Grade 100 polyethylene pipe materials. Simultaneously, the introduction of a certain amount of olefin block copolymer achieves a low-temperature toughening effect, which is superior to conventional toughening agents such as ethylene propylene rubber, POE, and SBS. Furthermore, while achieving low-temperature toughening, it avoids a decrease in the Vicat softening point. The introduction of conventional toughening agents leads to a significant decrease in the Vicat softening point, affecting the performance of corrosion-resistant polyethylene.

[0025] The polyethylene of this invention has good processing properties, and its notched impact strength at -45°C can reach 100 kJ / m. 2 The above-mentioned notched impact strength at -60℃ can reach up to 95kJ / m. 2 It has excellent low-temperature resistance and a suitable Vicat softening point.

[0026] In different embodiments, the amounts of each component in the low-temperature resistant polyethylene, by weight, can be as follows:

[0027] The amount of PERT resin can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, or any combination thereof.

[0028] The amount of olefin block copolymer can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, or any combination thereof;

[0029] The amount of metallocene linear low-density polyethylene can be 0 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, or any combination thereof.

[0030] The amount of UV-resistant filler can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, or any combination thereof;

[0031] The amount of antioxidant can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof.

[0032] In a specific embodiment of the present invention, the PERT resin includes at least one of PERT type I resin and PERT type II resin. Using a blend of PERT type I and PERT type II resins is more conducive to leveraging the entanglement between chain segments in the molecular structure, thereby significantly improving the low-temperature impact resistance and processability of polyethylene.

[0033] In a specific embodiment of the present invention, the PERT resin includes PERT Type I resin and PERT Type II resin. Further, the mass ratio of PERT Type I resin to PERT Type II resin is 1:(0.5-2), for example, it can be a range of 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, or any combination thereof, which further helps to improve the low-temperature impact resistance and processing performance of low-temperature resistant polyethylene.

[0034] In a specific embodiment of the present invention, the olefin block copolymer includes at least one of Infuse 9010, Infuse 9817, Infuse 9107, Infuse 9530, Infuse 9100, Infuse 9507, Infuse 9007, Infuse 9077, Infuse 9000, Infuse 9807, and Infuse 9900. The aforementioned olefin block copolymer is an olefin block copolymer (OBC) synthesized by Dow Chemical Company using a chain shuttle polymerization process. The inventors of this invention have discovered that the above-mentioned OBC contains amorphous ethylene-octene segments with low glass transition temperatures. Combined with its chain shuttle process, this results in unexpected effects in improving the low-temperature performance of polyethylene, significantly increasing the low-temperature impact strength of polyethylene without lowering its Vicat softening point and eliminating the risk of oil leakage.

[0035] In a specific embodiment of the present invention, the mass ratio of PERT resin to olefin block copolymer is (1.25 to 3.5):1, for example, it can be a range of 1.25:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1 or any two of these, thereby further improving the low-temperature impact resistance and ensuring a suitable Vicat softening point.

[0036] In a specific embodiment of the present invention, the density of the metallocene linear low-density polyethylene is 0.91–0.93 g / cm³. 3 For example, it could be 0.91 g / cm³. 3 0.915g / cm 3 0.92g / cm 3 0.925g / cm 3 0.93g / cm3 Or a range of any two of them; the melt index is 0.1 to 4 g / 10 min at 190℃ / 2.16 kg, for example, it can be 0.1 g / 10 min, 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min or a range of any two of them.

[0037] In a specific embodiment of the present invention, the UV-resistant filler includes titanium dioxide and / or carbon black. Further, the UV-resistant filler is titanium dioxide treated with a silane coupling agent and / or carbon black treated with a silane coupling agent, wherein the carbon black has a particle size ≤30nm. The titanium dioxide includes rutile titanium dioxide. The introduction of an appropriate amount of UV-resistant filler can resist ultraviolet radiation, reduce sunlight damage to the pipeline, and extend the service life of the corrosion-resistant pipeline.

[0038] In specific embodiments of the present invention, the antioxidant includes, but is not limited to, at least one of antioxidant 1010, antioxidant 168, and antioxidant B245, and may further include UV absorbers, light stabilizers, etc. The addition of antioxidants can, on the one hand, reduce the degradation of polyethylene materials during processing, and on the other hand, increase the oxidation induction period of the material, improve its thermal aging and photoaging properties, and effectively extend the service life of corrosion-resistant pipes.

[0039] In a specific embodiment of the present invention, the melt flow rate of the low-temperature resistant polyethylene at 190°C / 2.16 kg is ≥0.49 g / 10 min, for example, it can be a range of 0.49 g / 10 min, 0.5 g / 10 min, 0.52 g / 10 min, 0.55 g / 10 min, 0.58 g / 10 min, 0.6 g / 10 min or any combination thereof, thereby ensuring the good processability of the low-temperature resistant polyethylene of the present invention.

[0040] In a specific embodiment of the present invention, the notched impact strength of the low-temperature resistant polyethylene at -45℃ is ≥110kJ / m. 2 For example, it can be 110 kg / m 2 115kg / m 2 120kg / m 2 125kg / m 2 130kg / m 2 135kg / m 2 Or a range consisting of any two of these; Low-temperature resistant polyethylene with a notched impact strength ≥70kJ / m at -60℃. 2 For example, it can be 70kg / m 2 75kg / m 2 80kg / m 2 85kg / m 2 90kg / m2 95kg / m 2 The range of any two of these can be used to reduce the lower limit of the operating temperature of the 3PE anti-corrosion layer made of the polyethylene material of the present invention to below -60°C, thereby improving the stability of the 3PE anti-corrosion pipeline under low temperature operation.

[0041] In a specific embodiment of the present invention, the Vicat softening point of the low-temperature resistant polyethylene is 110-120°C.

[0042] The second aspect of the present invention provides a method for preparing low-temperature resistant polyethylene according to the first aspect of the present invention, comprising the following steps: mixing and extruding the low-temperature resistant polyethylene according to the composition of the first aspect of the present invention.

[0043] In a specific embodiment of the present invention, the temperature during extrusion granulation is 190–220°C. Extrusion granulation is performed using a twin-screw extruder, and conventional extrusion granulation parameters can be set accordingly.

[0044] The third aspect of the present invention provides a 3PE anti-corrosion layer, including a polyethylene anti-corrosion layer; the polyethylene anti-corrosion layer is mainly made of the low-temperature resistant polyethylene of the first aspect of the present invention.

[0045] Example 1

[0046] This embodiment provides low-temperature resistant polyethylene, comprising the following components by weight: 67 parts PERT resin, 20 parts olefin block copolymer, 10 parts metallocene linear low-density polyethylene, 2.2 parts UV-resistant filler, and 0.8 parts antioxidant.

[0047] The PEPR resin is a mixture of PERT Type I and PERT Type II resins in a mass ratio of 1:1, wherein the PERT Type I resin is Dow Chemical PE-RT 2344 and the PERT Type II resin is Dow Chemical PE-RT 2388; the olefin block copolymer is Infuse 9010 manufactured by Dow Chemical; and the density of the metallocene linear low-density polyethylene is 0.918 g / cm³. 3 The melt index is 1g / 10min at 190℃ / 2.16kg; the UV-resistant filler is carbon black treated with silane coupling agent, and the carbon black particle size is <30nm (Cabot PE6336).

[0048] The antioxidant is a mixture of antioxidant 1010, antioxidant 168, UV absorber UV-531, light stabilizer UV944 and antioxidant 245 in a mass ratio of 1:1:1:1:1:1.

[0049] This embodiment provides a method for preparing low-temperature resistant polyethylene, including the following steps: weighing each component according to the above proportions, mixing them evenly using a high-speed mixer, and then extruding and granulating them using a twin-screw extruder to obtain polyethylene granules. The twin-screw extruder parameters are set as follows: extruder zone 1 160℃, zone 2 200℃, zone 3 230℃, zone 4 230℃, zone 5 230℃, zone 6 230℃, zone 7 230℃, zone 8 230℃, die 220℃, main extruder speed 300 RPM, and feed rate 10 Hz.

[0050] Example 2

[0051] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 1, the only difference being the amount of each component used.

[0052] The low-temperature resistant polyethylene of this embodiment includes the following components by weight: 67 parts PERT resin, 10 parts olefin block copolymer, 20 parts metallocene linear low-density polyethylene, 2.2 parts UV-resistant filler and 0.8 parts antioxidant.

[0053] Example 3

[0054] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 1, the only difference being the amount of each component used.

[0055] The low-temperature resistant polyethylene of this embodiment includes the following components by weight: 57 parts PERT resin, 40 parts olefin block copolymer, 2.2 parts UV-resistant filler and 0.8 parts antioxidant.

[0056] Example 4

[0057] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 1, the only difference being the amount of each component used.

[0058] The low-temperature resistant polyethylene of this embodiment includes the following components by weight: 50 parts PERT resin, 20 parts olefin block copolymer, 27 parts metallocene linear low-density polyethylene, 2.2 parts UV-resistant filler and 0.8 parts antioxidant.

[0059] Example 5

[0060] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 1, the only difference being the amount of each component used.

[0061] The low-temperature resistant polyethylene of this embodiment includes the following components by weight: 80 parts PERT resin, 17 parts olefin block copolymer, 2.2 parts UV-resistant filler and 0.8 parts antioxidant.

[0062] Example 6

[0063] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 3, the only difference being that the ratio of PERT type I resin and PERT type II resin in the PEPR resin is different.

[0064] In this embodiment, the low-temperature resistant polyethylene uses a mixture of PERT type I resin and PERT type II resin in a mass ratio of 1:0.5.

[0065] Example 7

[0066] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 3, the only difference being that the ratio of PERT type I resin and PERT type II resin in the PEPR resin is different.

[0067] In this embodiment, the low-temperature resistant polyethylene uses a mixture of PERT type I resin and PERT type II resin in a mass ratio of 1:2.

[0068] Example 8

[0069] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 3, the only difference being that only PERT type I resin is used in the PEPR resin.

[0070] Example 9

[0071] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 3, the only difference being that only PERT type II resin is used in the PEPR resin.

[0072] Example 10

[0073] This embodiment refers to the low-temperature resistant polyethylene and its preparation method in Example 1, the only difference being the amount of each component used.

[0074] The low-temperature resistant polyethylene of this embodiment includes the following components by weight: 75 parts PERT resin, 22 parts olefin block copolymer, 2.2 parts UV-resistant filler and 0.8 parts antioxidant.

[0075] Comparative Example 1

[0076] Comparative Example 1 refers to the low-temperature resistant polyethylene and its preparation method of Example 1, the difference being that the components and amounts are different.

[0077] The polyethylene of Comparative Example 1 comprises the following components by weight: 20 parts of olefin block copolymer, 10 parts of metallocene linear low-density polyethylene, 67 parts of high-density polyethylene, 2.2 parts of UV-resistant filler, and 0.8 parts of antioxidant.

[0078] The high-density polyethylene used is grade 100 polyethylene pipe material with a melt index of 0.2 g / 10 min (190℃, 5 kg). The rest is the same as in Example 1.

[0079] Comparative Example 2

[0080] Comparative Example 2 refers to the low-temperature resistant polyethylene and its preparation method of Example 1, the difference being that the components and amounts are different.

[0081] The polyethylene of Comparative Example 2 comprises the following components by weight: 67 parts PERT resin, 10 parts metallocene linear low-density polyethylene, 20 parts EPDM rubber, 2.2 parts UV-resistant filler, and 0.8 parts antioxidant. The remainder is the same as in Example 1.

[0082] Comparative Example 3

[0083] Comparative Example 3 refers to the low-temperature resistant polyethylene and its preparation method of Example 1, the difference being that the components and amounts are different.

[0084] The polyethylene of Comparative Example 3 comprises the following components by weight: 60 parts high-density polyethylene, 10 parts metallocene linear low-density polyethylene, 30 parts EPDM rubber, 5 parts UV-resistant filler, 0.8 parts antioxidant, and 0.15 parts lubricant.

[0085] The high-density polyethylene is grade 100 polyethylene pipe material with a melt index of 0.2 g / 10 min (190℃, 5Kg); the UV-resistant filler is Cabot PE6336; the antioxidant is B215; the lubricant is zinc stearate; and the metallocene linear low-density polyethylene is the same as in Example 1.

[0086] Comparative Example 4

[0087] Comparative Example 4 refers to the low-temperature resistant polyethylene and its preparation method of Example 1, the difference being that the components and amounts are different.

[0088] The polyethylene of Comparative Example 4 comprises the following components by weight: 30 parts high-density polyethylene, 70 parts metallocene linear low-density polyethylene, 0.2 parts organic peroxide, 2 parts polyethylene wax, 5 parts UV-resistant filler, and 0.5 parts antioxidant.

[0089] Among them, the high-density polyethylene is grade 100 polyethylene pipe material with a melt index of 0.2 g / 10 min (190℃, 5Kg); the organic peroxide is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the polyethylene wax is homopolymer polyethylene wax; the UV-resistant filler is Cabot PE6336; the antioxidant is B215; and the metallocene linear low-density polyethylene is the same as in Example 1.

[0090] Comparative Example 5

[0091] Comparative Example 5 refers to the low-temperature resistant polyethylene and its preparation method of Example 1, the difference being that the components and amounts are different.

[0092] The polyethylene of Comparative Example 5 comprises the following components by weight: 80 parts high-density polyethylene, 10 parts SEPS, 10 parts plasticizer, 0.6 parts antioxidant and 0.2 parts ultraviolet absorber.

[0093] Among them, the high-density polyethylene is grade 100 polyethylene pipe material with a melt index of 0.2g / 10min (190℃, 5Kg); SEPS is Kronen G1701; plasticizer is white oil; antioxidant is B215; and ultraviolet absorber is UV-531.

[0094] Experimental Example

[0095] The performance of polyethylene materials from different embodiments and comparative examples was tested as follows, and the test results are shown in Table 1.

[0096] Melt flow rate: The flow rate of 2.16 kg melt at 190℃ was tested according to GB / T 3682-2018.

[0097] Vicat softening point: The test method shall be carried out in accordance with GB / T 1633-2000;

[0098] Oxidation induction period: conducted according to GB / T23257-2017, test temperature 220℃;

[0099] Impact strength of notched simply supported beams: After being kept at -45℃ and -60℃ for 24 hours, the test was conducted in accordance with GB / T 1043.1-2008.

[0100] Oil seepage test: Place the granulated particles in a 50℃ oven for 30 days and observe the oil seepage.

[0101] Table 1 Test results of different polyethylene materials

[0102]

[0103] The test results above show that the polyethylene of this invention has good processing performance, and its notched impact strength at -45℃ can reach 100kJ / m. 2 The highest value can reach 135 kJ / m 2 The notched impact strength at -60℃ can reach up to 95kJ / m. 2 It has excellent low-temperature resistance.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Low-temperature resistant polyethylene, characterized in that, Includes the following components by weight: The mixture consists of 50-80 parts PERT resin, 10-40 parts olefin block copolymer, 0-30 parts metallocene linear low-density polyethylene, 1-3 parts UV-resistant filler, and 0.3-1 parts antioxidant. The PERT resin includes PERT type I resin and PERT type II resin in a mass ratio of 1:(0.5 to 1.2); The mass ratio of the PERT resin to the olefin block copolymer is (1.25~3.5):

1.

2. The low-temperature resistant polyethylene according to claim 1, characterized in that, The olefin block copolymer includes at least one of Infuse 9010, Infuse 9817, Infuse 9107, Infuse 9530, Infuse 9100, Infuse 9507, Infuse 9007, Infuse 9077, Infuse 9000, Infuse 9807, and Infuse 9900.

3. The low-temperature resistant polyethylene according to claim 1, characterized in that, The density of the metallocene linear low-density polyethylene is 0.91–0.93 g / cm³. 3 At 190℃ / 2.16kg, the melt index is 0.1~4g / 10min.

4. The low-temperature resistant polyethylene according to claim 1, characterized in that, The low-temperature resistant polyethylene has a melt flow rate ≥0.49g / 10min at 190℃ / 2.16kg.

5. The low-temperature resistant polyethylene according to claim 1, characterized in that, The low-temperature resistant polyethylene has a notched impact strength ≥120kJ / m at -45℃. 2 .

6. The low-temperature resistant polyethylene according to claim 1, characterized in that, The low-temperature resistant polyethylene has a notched impact strength ≥75kJ / m at -60℃. 2 .

7. The method for preparing low-temperature resistant polyethylene according to any one of claims 1 to 6, characterized in that, The process includes the following steps: weighing each component according to the proportion, mixing, and extruding granulation. 8.3PE anti-corrosion layer, characterized in that, It includes a polyethylene anti-corrosion layer; the polyethylene anti-corrosion layer is mainly made of the low-temperature resistant polyethylene as described in any one of claims 1 to 6.

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