Easily-processed high-impact polyethylene as well as preparation method and application thereof

Abstract

The invention discloses easy-to-process high-impact polyethylene as well as a preparation method and application thereof. The weight-average molecular weight of the easy-to-process high-impact polyethylene is 10 * 10 < 4 >-45 * 10 < 4 > g / mol, the molecular weight distribution is 20-40, the density is 0.940-0.965 g / cm < 3 >, the melt index is 8-15g / 10min, the branched chain content is 0.2-1.0 C / 1000C, the normal-temperature simply supported beam double-notch impact strength (23 DEG C) is greater than or equal to 50kJ / m < 2 >, and the low-temperature simply supported beam double-notch impact strength (-40 DEG C) is greater than or equal to 28kJ / m < 2 >. The easy-to-process high-impact polyethylene has the characteristics of wide processing temperature window, easy processing and high impact strength.

Description

Technical Field

[0001] The invention relates to a polyolefin material, in particular to an easy-to-process high-impact polyethylene and a preparation method and application thereof. Background Art

[0002] Polyethylene rotomolding plastics are widely used in rotomolding storage tanks, rotomolding water tanks, rotomolding inspection wells, slide-type amusement equipment and other fields. At present, more than 99% of the rotomolding raw materials required for domestic rotomolding production are polyethylene, and 65% of them are linear low-density polyethylene LLDPE, 20% are cross-linked polyethylene XLPE, 10% are high-density polyethylene HDPE, and 5% are low-density polyethylene LDPE. LLDPE is particularly suitable for rotomolding due to its wide processing window and excellent impact performance. However, it has obvious deficiencies in low-temperature impact resistance, high temperature resistance, environmental stress cracking resistance and thermal expansion resistance. In order to meet the requirements of high temperature resistance, high impact resistance and high environmental stress cracking resistance, rotomolding grade XLPE is currently used. However, XLPE has problems such as narrow processing window, high scrap rate, high equipment requirements, low processing fluidity and low production efficiency. It can be seen that how to balance the processing performance and normal temperature / low temperature impact resistance of polyethylene rotomolding plastics is the key.

[0003] Copolymer HDPE has a non-cross-linked structure, and its melt index and processing performance are significantly better than XLPE. The molecular chain of copolymer HDPE has a certain amount of long chain branching and / or short chain branching structure, which has certain advantages in impact strength and environmental stress cracking resistance.

[0004] In summary, the present invention aims to develop a polyethylene resin and a preparation method that have both easy processing, wide processing window characteristics and high impact strength. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide an easy-to-process high-impact polyethylene and a preparation method and application thereof. The easy-to-process high-impact polyethylene has the characteristics of a wide processing temperature window, easy processing and high impact strength.

[0006] According to one object of the present invention, the present invention provides an easily processable high impact polyethylene, wherein the weight average molecular weight of the easily processable high impact polyethylene is in the range of 10×10 4 -45×10 4 g / mol, molecular weight distribution is 20-40, density is 0.940-0.965g / cm 3 , melt index is 8-15g / 10min, branch content is 0.2-1.0C / 1000C, room temperature simple supported beam double notch impact strength (23℃) ≥50kJ / m 2Low temperature simply supported double notch impact strength (-40℃) ≥28kJ / m 2 .

[0007] The present invention also provides a method for preparing the easily processable high-impact polyethylene, which comprises:

[0008] In a first reactor, polymer A is dissolved in solvent B, cocatalyst C and catalyst D are added in sequence, α-olefin E and ethylene are introduced to start polymerization reaction, the polymerization temperature is T1, the polymerization time is t, the polymerization pressure is P1, after the polymerization reaction is completed, the slurry in the first reactor is introduced into a product collection tank at a flow rate X1 (the flow rate is based on the weight of the solid phase product); the concentration of polymer A in the first reactor is 0.1-10.0wt%, and the weight average molecular weight of polymer A is 1000-8000g / mol;

[0009] At the same time, in the second reactor, solvent B is used as the polymerization medium, the polymerization temperature is T2, the polymerization pressure is P2, and the cocatalyst F, catalyst G, α-olefin H and ethylene are continuously introduced for continuous production, and the slurry in the second reactor is introduced into the product collection tank at a flow rate of X2 (the flow rate is based on the weight of the solid phase product);

[0010] The first reactor and the second reactor are operated in parallel;

[0011] The mixed slurry in the product collection tank is introduced into a solid-liquid separator, the temperature of the solid-liquid separator is T3, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, and extruded and granulated to obtain the easy-to-process high-impact polyethylene product. The separated liquid phase product can be further refined to obtain solvent B for use in the first reactor and the second reactor.

[0012] According to a preferred embodiment of the present invention, polymer A is selected from one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, polybutene, paraffin wax, and Fischer-Tropsch wax.

[0013] According to a preferred embodiment of the present invention, the concentration of polymer A in the first reaction kettle is 0.1-10.0wt%, and solvent B is selected from one or more of n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, methylcyclohexane, 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, n-octane, 2-methylheptane, 3-methylheptane, n-nonane and n-decane; cocatalyst C and cocatalyst F are selected from methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, butylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylamine ... One or more of butylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum monochloride, ethylaluminum dichloride, triphenylborane, tri(4-fluorophenyl)borane, tri(pentafluorophenyl)borane, tri(3,5-difluorophenyl)borane, tri(2,4,6-trifluorophenyl)borane, and the cocatalyst C and the cocatalyst F may be the same or different; the catalyst D and the catalyst G are selected from one or more of a metallocene catalyst, a late transition metal catalyst, a Ziegler-Natta catalyst, a non-metallocene catalyst, and a FI catalyst, and the catalyst D and the catalyst G may be the same or different;

[0014] The α-olefin E and α-olefin H are selected from one or more of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene, and the α-olefin E and α-olefin H may be the same or different; the addition amount of the α-olefin E and α-olefin H usually needs to be selected in accordance with the catalytic activity of the catalyst to ensure that the branch content in the final product is 0.2-1.0C / 1000C.

[0015] The polymerization temperature T1 is 50-90°C, the polymerization time t is 0.5-10h, and the polymerization pressure P1 is 0.5-2.0MPa.

[0016] According to a preferred embodiment of the present invention, the content of polymer A contained in the solid phase product in the slurry in the first reactor is 0.5-8.0wt%, the weight average molecular weight of polymer A is 1000-8000g / mol, and the weight average molecular weight of the solid phase product in the slurry in the first reactor is 80-140×10 4 g / mol, molecular weight distribution is 50-500, branch content is 0.2-1.0C / 1000C, and the initial elastic modulus of the solid phase product after removing polymer A is 0.2-0.5MPa.

[0017] According to a preferred embodiment of the present invention, polymer A is widely distributed on the surface and inside particles of the solid phase product in the slurry in the first reactor, and the surface of the solid phase product is flaky. Polymer A is distributed between the flaky crystals, and the thickness of the flaky crystals is 10-300nm.

[0018] According to a preferred embodiment of the present invention, the polymerization temperature T2 is 60-100°C, the polymerization pressure P2 is 0.5-2.0 MPa, and the solid-liquid separator temperature T3 is 40-55°C.

[0019] According to a preferred embodiment of the present invention, the ratio of the slurry flow rate X1 in the first reactor to the slurry flow rate X2 in the second reactor is 1:(1.5-9.9), and the polymer A content in the easy-to-process high-impact polyethylene product is 0.3-2.0wt%. The weight average molecular weight of the solid phase product in the slurry in the second reactor is 20×10 4 -45×10 4 g / mol, molecular weight distribution is 10-25.

[0020] According to a preferred embodiment of the present invention, the high temperature gel chromatography test spectrum of the easy-to-process high-impact polyethylene product presents an obvious bimodal distribution.

[0021] According to the second object of the present invention, the present invention provides the use of the easily processable high-impact polyethylene prepared by the method in the preparation of impact-resistant polyethylene products.

[0022] According to a preferred embodiment of the present invention, the easy-to-process high-impact polyethylene is mixed with a plasticizer, a lubricant, a stabilizer and an antioxidant in a weight ratio of (96.5-99.0): (0.1-1.0): (0.1-1.0): (0.1-1.0): (0.1-1.0), and then melt-blended and granulated (granulation temperature 190-230°C, rotation speed 100-250rpm). A rotational molding process is adopted, with a rotational molding temperature of 180-260°C and a molding time of 4-72h. Impact-resistant polyethylene products, such as small hollow, medium hollow and large hollow products with high impact strength, can be prepared. These products can be used in automotive urea tanks, airdrop boxes, automobile fuel tanks, automobile oil drums, chemical container boxes and other fields with high impact requirements. Among them, the plasticizer can be di(2-ethylhexyl) phthalate, dibutyl phthalate, diisobutyl phthalate, dibutyl sebacate, di(2-ethylhexyl) sebacate and other commonly used plasticizers in the art; the lubricant can be calcium stearate, zinc stearate, aluminum stearate, silicone oil and other commonly used lubricants in the art; the stabilizer can be diphenylthiourea, α-phenylindole, melamine, zinc oxide, 2-hydroxy-4-methoxybenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone and other commonly used stabilizers in the art; the antioxidant is used to alleviate the auto-oxidation rate of polymer materials, and can be 1010 antioxidant, 1076 antioxidant, 626 antioxidant, AT-215 antioxidant and other commonly used antioxidants in the art.

[0023] The present invention has the following outstanding gain effects:

[0024] (1) The easy-to-process high-impact polyethylene of the present invention has a wide molecular weight distribution, and the polymer A component can melt quickly and has a strong molecular chain movement ability, which can promote the movement of high molecular weight polyethylene molecular chains around the polymer A molecular chains. Therefore, the processing temperature required during the melt processing is lower, and the processability and processing economy are better.

[0025] (2) The easy-to-process high-impact polyethylene of the present invention is produced by a dual-reactor parallel process. The molecular weight of the solid phase product in the first reactor is distributed in the range of 50-500, and the initial elastic modulus of the solid phase product after removing polymer A is 0.2-0.5 MPa, which indicates that the solid phase product in the first reactor has the characteristic of low entanglement. The molecular chain movement ability of low-entanglement polyethylene is stronger, and the reentanglement behavior will occur more quickly during the melt processing. The more rapid and sufficient the reentanglement behavior is, the higher the room temperature impact strength and low temperature impact strength of polyethylene will be. In addition, the weight average molecular weight of the solid phase product in the slurry in the first reactor is 80-140×10 4 g / mol, this low entanglement polyethylene has the characteristics of high molecular weight. According to the knowledge in the field of polymer physics, the higher the molecular weight, the more entanglement points will be formed after the molecular chains are entangled. More entanglement points will also lead to higher room temperature impact strength and low temperature impact strength of the polyethylene product.

[0026] (3) The easy-to-process high-impact polyethylene of the present invention is a non-cross-linked polyethylene, and has a molecular weight distribution of 20-40 and a melt index of 8-15 g / 10 min, which indicates that it has better processing performance, a wider processing temperature window range, and the influence of fluctuations in processing temperature conditions on product performance is controllable.

[0027] (4) The easy-to-process high-impact polyethylene of the present invention is a non-cross-linked polyethylene with a branch content of 0.2-1.0C / 1000C. The insertion of an appropriate amount of branches is beneficial to improving the environmental stress cracking resistance of polyethylene products. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the elastic modulus G'-time t curve of the solid phase product in the first reaction kettle after removing polymer A at 160°C.

[0029] Figure 2 This is a scanning electron microscope image of the surface of the solid phase product particles in the first reaction kettle after removing polymer A. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0031] The following methods were used to test the structure or properties of the polyolefins produced in the examples described:

[0032] High temperature gel permeation chromatography (GPC) is used to test the weight average molecular weight and molecular weight distribution of polyethylene.

[0033] Gradient densitometer is used to test the density of polyethylene.

[0034] The melt index meter is used to test the melt index of polyethylene.

[0035] Analytical temperature rising elution fractionation (TREF) is used to measure the short chain branch content of polyethylene.

[0036] The impact testing machine is used to test the room temperature impact strength and low temperature impact strength of polyethylene.

[0037] The polymer A content in the polyethylene product was separated by heating and eluting with xylene and the mass content was calculated by weighing.

[0038] Rotational rheometer is used to test the initial elastic modulus of polyethylene.

[0039] Scanning electron microscopy was used to test the surface morphology of polyethylene samples.

[0040] Example 1

[0041] 150 kg of Fischer-Tropsch wax (weight average molecular weight 1200 g / mol) was dissolved in the first reaction kettle (medium hexane, volume 10 m 3 ), 1.1L triethylaluminum, 15g Ziegler-Natta catalyst, 50L 1-hexene were added in sequence, ethylene was introduced to start polymerization, the polymerization temperature was 52°C, the polymerization time (residence time) was 3h, and the polymerization pressure was 1.1MPa; the second reactor (volume 40m 3) with hexane as polymerization medium, polymerization temperature of 85°C, polymerization pressure of 1.5MPa, continuously introducing triethylaluminum, Ziegler-Natta catalyst, 1-hexene and ethylene for continuous production; the first reactor and the second reactor are produced in parallel, the slurry in the first reactor is introduced into the product collection tank at 1t / h, and the slurry in the second reactor is introduced into the product collection tank at 6t / h. The mixed slurry in the product collection tank is introduced into a solid-liquid separator, the temperature of the solid-liquid separator is 45°C, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain an easy-to-process high-impact polyethylene product a. The analysis and characterization results of product a are shown in Table 1.

[0042] Example 2

[0043] 125 kg of polyethylene wax (weight average molecular weight 2000 g / mol) was dissolved in the first reaction kettle (medium: heptane, volume 10 m 3 ), 1.2L triisobutylaluminum, 18g Ziegler-Natta catalyst, 60L 1-hexene were added in sequence, ethylene was introduced to start polymerization, the polymerization temperature was 62°C, the polymerization time (residence time) was 3.5h, and the polymerization pressure was 0.7MPa; the second reactor (volume 40m 3 ) with heptane as polymerization medium, polymerization temperature of 89°C, polymerization pressure of 1.9MPa, continuously introducing triisobutylaluminum, Ziegler-Natta catalyst, 1-hexene and ethylene for continuous production; the first reactor and the second reactor are produced in parallel, the slurry in the first reactor is introduced into the product collection tank at 1.1t / h, and the slurry in the second reactor is introduced into the product collection tank at 5.5t / h. The mixed slurry in the product collection tank is introduced into a solid-liquid separator, the temperature of the solid-liquid separator is 50°C, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain an easy-to-process high-impact polyethylene product b. The analysis and characterization results of product b are shown in Table 1.

[0044] Example 3

[0045] 100 kg of oxidized polyethylene wax (weight average molecular weight 3200 g / mol) was dissolved in the first reaction kettle (medium cyclohexane, volume 10 m 3 ), 1.3L modified methylaluminoxane, 16g supported metallocene catalyst, 30L 1-hexene, 30L 1-octene were added in sequence, ethylene was introduced to start polymerization, the polymerization temperature was 71°C, the polymerization time (residence time) was 2.2h, and the polymerization pressure was 1.6MPa; the second reactor (volume 40m 3) with cyclohexane as polymerization medium, polymerization temperature of 80°C, polymerization pressure of 1.2MPa, continuously introducing modified methylaluminoxane, supported metallocene catalyst, 1-hexene and ethylene for continuous production; the first reactor and the second reactor are produced in parallel, the slurry in the first reactor is introduced into the product collection tank at 0.9t / h, and the slurry in the second reactor is introduced into the product collection tank at 3.6t / h. The mixed slurry in the product collection tank is introduced into the solid-liquid separator, the temperature of the solid-liquid separator is 53°C, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain the easy-to-process high-impact polyethylene product c. The analysis and characterization results of product c are shown in Table 1.

[0046] Example 4

[0047] 200 kg of polyethylene wax (weight average molecular weight 6000 g / mol) was dissolved in the first reaction kettle at a concentration of 4.0 wt% (medium: n-hexane, volume 10 m 3 ), 0.8L triethylaluminum, 14g Ziegler-Natta catalyst, 70L 1-hexene were added in sequence, ethylene was introduced to start polymerization, the polymerization temperature was 75°C, the polymerization time (residence time) was 4h, and the polymerization pressure was 0.9MPa; the second reactor (volume 40m 3 ) with n-hexane as polymerization medium, polymerization temperature of 85°C, polymerization pressure of 1.3MPa, continuously introducing triethylaluminum, supported metallocene catalyst, 1-hexene and ethylene for continuous production; the first reactor and the second reactor are produced in parallel, the slurry in the first reactor is introduced into the product collection tank at 1.5t / h, and the slurry in the second reactor is introduced into the product collection tank at 4.6t / h. The mixed slurry in the product collection tank is introduced into the solid-liquid separator, the temperature of the solid-liquid separator is 42°C, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain an easy-to-process high-impact polyethylene product d. The analysis and characterization results of product d are shown in Table 1.

[0048] Comparative Example 1

[0049] The first reactor (volume 10m 3 ) with n-hexane as polymerization medium, 0.9L triethylaluminum, 12g Ziegler-Natta catalyst, 50L 1-hexene were added in sequence, ethylene was introduced to start polymerization, the polymerization temperature was 69°C, the polymerization time (residence time) was 4.5h, and the polymerization pressure was 0.6MPa; the second reactor (volume 40m 3) with n-hexane as polymerization medium, polymerization temperature of 88°C, polymerization pressure of 1.3MPa, continuously introducing triethylaluminum, Ziegler-Natta catalyst, 1-hexene and ethylene for continuous production; the first reactor and the second reactor are produced in parallel, the slurry in the first reactor is introduced into the product collection tank at 1.3t / h, and the slurry in the second reactor is introduced into the product collection tank at 4.6t / h. The mixed slurry in the product collection tank is introduced into a solid-liquid separator, the temperature of the solid-liquid separator is 44°C, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain polyethylene product e. The analysis and characterization results of product e are shown in Table 1.

[0050] Table 1 Polyethylene ae characterization results

[0051]

[0052]

[0053] As shown in Table 1 above, the polyethylene products ad of Examples 1-4 have higher melt index, wider molecular weight distribution, higher room temperature impact strength and low temperature impact strength than the polyethylene product e in Comparative Example 1, which indicates that the polyethylene products ad have better processability and high impact resistance. In addition, the content of polymer A in the polyethylene products ad is higher, and the initial elastic modulus of the solid phase product in the first reactor after removing polymer A is lower (0.25-0.39 MPa, see Appendix Figure 1 ), and the surface of the solid phase product in the first reactor after removing polymer A is scaly (see attached Figure 2 ). The polyethylene product e does not contain polymer A, the initial elastic modulus of the solid phase product in the first reactor is as high as 0.86MPa, and the surface of the solid phase product has no obvious flaky lamella structure. The above results show that the molecular chain of the polyethylene product E is highly entangled. Affected by the entanglement point, the molecular chain is difficult to open quickly, the molecular chain has weak mobility, and it is difficult to quickly undergo reentanglement, which leads to a low melt index of the polyethylene product e, greater processing difficulty, reduced economic efficiency of the processing process, and low room temperature impact strength and low low temperature impact strength of the final product.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An easy-to-process high-impact polyethylene, characterized in that: The weight average molecular weight of the easy-to-process high-impact polyethylene is 10×10 4 -45×10 4 g / mol, molecular weight distribution is 20-40, density is 0.940-0.965g / cm 3 , melt index is 8-15g / 10min, branch content is 0.2-1.0C / 1000C, room temperature simple supported beam double notch impact strength (23℃) ≥50kJ / m 2 Low temperature simply supported double notch impact strength (-40℃) ≥28kJ / m 2 .

2. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: The easy-to-process high-impact polyethylene is prepared by the following steps: In the first reactor, polymer A is dissolved in solvent B, cocatalyst C and catalyst D are added in sequence, α-olefin E and ethylene are introduced to start polymerization reaction, the polymerization temperature is T1, the polymerization time is t, the polymerization pressure is P1, after the polymerization reaction is completed, the slurry in the first reactor is introduced into the product collection tank at a flow rate of X1; the concentration of polymer A in the first reactor is 0.1-10.0wt%, and the weight average molecular weight of polymer A is 1000-8000g / mol; At the same time, in the second reactor, solvent B is used as the polymerization medium, the polymerization temperature is T2, the polymerization pressure is P2, and the cocatalyst F, catalyst G, α-olefin H and ethylene are continuously introduced for continuous production, and the slurry in the second reactor is introduced into the product collection tank at a flow rate of X2; The first reactor and the second reactor are operated in parallel; The mixed slurry in the product collection tank is introduced into a solid-liquid separator, the temperature of the solid-liquid separator is T3, and the solid phase product separated by the solid-liquid separator is dried, devolatilized, extruded and granulated to obtain the easy-to-process high-impact polyethylene product.

3. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: The polymer A is selected from one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, polybutene, paraffin wax, and Fischer-Tropsch wax.

4. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: Solvent B is selected from one or more of n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, methylcyclohexane, 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, n-octane, 2-methylheptane, 3-methylheptane, n-nonane and n-decane; The cocatalyst C and the cocatalyst F are selected from one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, butylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum monochloride, ethylaluminum dichloride, triphenylborane, tri(4-fluorophenyl)borane, tri(pentafluorophenyl)borane, tri(3,5-difluorophenyl)borane, and tri(2,4,6-trifluorophenyl)borane, and the cocatalyst C and the cocatalyst F may be the same or different; Catalyst D and catalyst G are selected from one or more of metallocene catalysts, late transition metal catalysts, Ziegler-Natta catalysts, non-metallocene catalysts, and FI catalysts, and catalyst D and catalyst G may be the same or different; α-olefin E and α-olefin H are selected from one or more of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene, and α-olefin E and α-olefin H may be the same or different; The polymerization temperature T1 is 50-90°C, the polymerization time t is 0.5-10h, and the polymerization pressure P1 is 0.5-2.0MPa.

5. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: The solid phase product in the slurry in the first reaction kettle contains a polymer A content of 0.5-8.0 wt %, and the weight average molecular weight of the solid phase product in the slurry in the first reaction kettle is 80-140×10 4 g / mol, molecular weight distribution is 50-500, branch content is 0.2-1.0C / 1000C, and the initial elastic modulus of the solid phase product after removing polymer A is 0.2-0.5MPa.

6. The easy-to-process high-impact polyethylene according to claim 4, characterized in that: The polymer A is distributed on the surface and inside the particles of the solid phase product in the slurry in the first reaction kettle, and the surface of the solid phase product is flaky. The polymer A is distributed between the flaky crystals, and the thickness of the flaky crystals is 10-300nm.

7. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: The polymerization temperature T2 is 60-100°C, the polymerization pressure P2 is 0.5-2.0MPa, and the solid-liquid separator temperature T3 is 40-55°C.

8. The easy-to-process high-impact polyethylene according to claim 1, characterized in that: The flow rate X1 and the flow rate X2 are both measured by weight of the solid phase product, the ratio of the slurry flow rate X1 in the first reactor to the slurry flow rate X2 in the second reactor is 1:(1.5-9.9), and the polymer A content in the easy-to-process high-impact polyethylene product is 0.3-2.0wt%; the weight average molecular weight of the solid phase product in the slurry in the second reactor is 20×10 4 -45×10 4 g / mol, molecular weight distribution is 10-25.

9. Use of the easily processable high-impact polyethylene according to any one of claims 1 to 8 in the preparation of impact-resistant polyethylene products.

10. The use according to claim 9, characterized in that: The easy-to-process high-impact polyethylene is mixed with a plasticizer, a lubricant, a stabilizer and an antioxidant in a weight ratio of (96.5-99.0): (0.1-1.0): (0.1-1.0): (0.1-1.0): (0.1-1.0), and after melt blending and granulation, a rotational molding process is adopted, with a rotational molding temperature of 180-260° C. and a molding time of 4-72 hours to prepare an impact-resistant polyethylene product.

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