High-melt-strength tensile polyethylene as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to high-melt-strength tensile polyethylene as well as a preparation method and application thereof. The high-melt-strength tensile polyethylene provided by the invention is prepared from the following raw materials in parts by weight: 30 to 60 parts of high-density polyethylene, 10 to 35 parts of metallocene polyethylene, 15 to 25 parts of a toughening agent, 2 to 7 parts of a composite additive and 0.1 to 0.3 part of an antioxidant, the composite additive is prepared from bicyclo [2.2. 1] heptane-2, 3-dicarboxylic acid disodium salt and poly (3-methyl-1-butene). The metallocene polyethylene is embedded into the high-density polyethylene, so that the deformation resistance of the system can be improved, and the toughening agent is used for changing the toughness of the mixed system; according to the present invention, the specific composite additive is selected and added, such that the nucleation ability and the crystallization property of the crystal can be improved through the synergism, the compatibility between the metallocene and the toughening agent can be improved so as to improve the tensile property of the material, such that the high melt strength and the tensile strength of the high melt strength stretch-resistant polyethylene can be provided with the high melt strength and the high tensile strength.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high melt strength tensile polyethylene, its preparation method, and its application. Background Technology

[0002] With the continuous development of production technology, the applications and fields of polyethylene have been greatly expanded. However, different processing and application fields have put forward higher requirements for polyethylene formulations. At present, ordinary low melt strength polyethylene has low melt strength, poor resistance to sag, and weak mechanical properties, which greatly limits its application in foaming, thermoforming, blow molding, extrusion coating and other processes. Melt strength is a very important parameter in the polyethylene processing process. High melt strength polyethylene has unparalleled advantages over ordinary low melt strength polyethylene in processing such as extrusion coating, blow molding, profile extrusion, and thermoforming.

[0003] Currently, there are three methods to improve the melt strength of polyethylene: reactor polymerization, electron irradiation, and blending. Reactor polymerization, as the name suggests, directly polymerizes polyethylene in a reactor to produce high melt strength. However, this method is difficult to develop due to the high complexity of the polymerization process conditions, requiring the selection of suitable catalysts and precise catalytic control technology. Electron irradiation uses electron beams to irradiate the polyethylene molecular chains, generating free radicals that trigger a chemical reaction. This method not only yields polymers with long-chain branched structures but also achieves a bimodal molecular weight distribution. However, the product requires subsequent processing to eliminate residual free radicals, resulting in complex equipment and high investment costs. Blending mostly employs melt blending, where polyethylene is uniformly mixed with other resins under strong shear forces in processing equipment. This method is simple and low-cost, but the blends often exhibit poor compatibility, making it difficult to produce products that balance high melt strength and high tensile strength. Summary of the Invention

[0004] This invention provides a high melt strength tensile polyethylene, its preparation method, and its application, to solve the problem that polyethylene prepared by blending method is difficult to achieve both high melt strength and tensile strength.

[0005] In a first aspect, the present invention provides a high melt strength tensile polyethylene, wherein, by weight, the raw materials include 30-60 parts of high-density polyethylene, 10-35 parts of metallocene polyethylene, 15-25 parts of toughening agent, 2-7 parts of composite additive, and 0.1-0.3 parts of antioxidant. The composite additive is composed of disodium bicyclo[2.2.1]heptane-2,3-dicarboxylic acid and poly3-methyl-1-butene.

[0006] In one optional embodiment, the high-density polyethylene has a density of 0.945 g / cm³. 3~0.955g / cm 3 The melt index (190℃ / 5kg) is 0.22-0.25g / 10min, and the weight-average molecular weight is 2.5x10. 5 -2.7x10 5 g / mol; In one optional embodiment, the high-density polyethylene has a density of 0.950 g / cm³. 3 Melt index (190℃ / 5kg) is 0.23g / 10min, weight-average molecular weight is 2.67x10 5 g / mol; In one alternative embodiment, the high-density polyethylene is Wanhua 23050.

[0007] In one alternative embodiment, the metallocene catalyst has a density of 0.910 g / cm³. 3 ~0.930 cm 3 The melt index (190℃ / 2.16kg) is 0.8-1.1g / 10min; In one optional embodiment, the metallocene polyethylene has a density of 0.920 g / cm3 and a melt index (190℃ / 2.16 kg) of 1.0 g / 10 min.

[0008] In one alternative embodiment, the metallocene polyethylene is Mobil 2010.

[0009] In one alternative embodiment, the toughening agent includes at least one of ethylene-octene block copolymer and ethylene-octene copolymer.

[0010] In one optional embodiment, the ethylene-octene block copolymer has a density of 0.870 g / cm3 to 0.880 g / cm3 and a melt index (190℃ / 2.16 kg) of 0.4-0.6 g / 10 min.

[0011] In one optional embodiment, the ethylene-octene block copolymer has a density of 0.877 g / cm3 and a melt index (190°C / 2.16 kg) of 0.5 g / 10 min.

[0012] In one optional embodiment, the ethylene-octene copolymer has a density of 0.860 g / cm3 to 0.870 g / cm3 and a melt index (190℃ / 2.16 kg) of 4-6 g / 10 min.

[0013] In one optional embodiment, the ethylene-octene copolymer has a density of 0.865 g / cm3 and a melt index (190°C / 2.16 kg) of 5 g / 10 min.

[0014] In one optional embodiment, the antioxidant includes at least two of hindered phenolic antioxidants, phosphorous antioxidants, and aromatic amine antioxidants.

[0015] In one alternative embodiment, the degree of polymerization of poly-3-methyl-1-butene is 600-1500.

[0016] In one alternative embodiment, the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly3-methyl-1-butene is (4.5-5.5):(4.5-5.5). In one alternative embodiment, the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt to poly3-methyl-1-butene is 5:5.

[0017] In one optional embodiment, the high melt strength tensile polyethylene has a melt strength of 0.25-0.6 N and a tensile strength of 25-41 MPa.

[0018] Secondly, the present invention also provides a method for preparing the high melt strength tensile polyethylene described above, wherein the raw materials are mixed and then subjected to a melt reaction, followed by extrusion and granulation to obtain the high melt strength tensile polyethylene.

[0019] In one alternative embodiment, the melt reaction, extrusion, and granulation are carried out in a twin-screw extruder.

[0020] In one alternative embodiment, the controllable temperature of the twin-screw extruder is 100~350°C; for example, 100°C, 150°C, 200°C, 250°C, 300°C or 350°C.

[0021] In one optional embodiment, the main screw speed of the twin-screw extruder is 300~600 r / min; for example, 300 r / min, 325 r / min, 350 r / min, 375 r / min, 400 r / min, 425 r / min, 450 r / min, 475 r / min, 500 r / min, 525 r / min, 550 r / min, 575 r / min, or 600 r / min.

[0022] In one alternative embodiment, a devolatilization system is provided in the middle and end sections of the extruder.

[0023] In one optional embodiment, the temperature of the extruder's feed section is controlled as follows: Zone 1: 125~165℃ (e.g., 125℃, 130℃, 135℃, 140℃, 150℃, 160℃, or 165℃); Zone 2: 150~210℃ (e.g., 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, or 210℃); Zone 3: 160~240℃ (e.g., 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, or 240℃); Zone 4: 170~250℃ (e.g., 170℃, 185℃, 200℃, 225℃, or 250℃); Zone 5: 180~2... Zone 40℃ (e.g., 180℃, 190℃, 200℃, 210℃ or 220℃, 230℃ or 240℃), Zone 6 temperature 180~220℃ (e.g., 180℃, 190℃, 200℃, 210℃ or 220℃), Zone 7 temperature 180~220℃ (e.g., 180℃, 190℃, 200℃, 210℃ or 220℃), Zone 8 temperature 170~200℃ (e.g., 170℃, 180℃, 195℃, 200℃), Zone 9 temperature 180~215℃ (e.g., 180℃, 195℃, 200℃, 205℃ or 215℃), Zone 10 temperature 195~210℃ (e.g., 195℃, 200℃, 205℃ or 210℃).

[0024] Thirdly, the present invention also provides the application of the high melt strength tensile polyethylene described above or the high melt strength tensile polyethylene prepared by the preparation method described above in extrusion coating, blow molding, profile extrusion, and thermoforming.

[0025] The technical solution of this invention has the following advantages: The high melt strength tensile polyethylene provided in this application comprises, by weight, 30-60 parts high-density polyethylene, 10-35 parts metallocene polyethylene, 15-25 parts toughening agent, 2-7 parts composite additive, and 0.1-0.3 parts antioxidant; the composite additive is composed of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly3-methyl-1-butene. Embedding metallocene polyethylene into high-density polyethylene improves the system's resistance to deformation, while the toughening agent alters the toughness of the mixture. By selecting and adding specific composite additives, their synergistic effect not only enhances crystal nucleation ability and crystallization performance but also improves the compatibility between the metallocene and the toughening agent, thereby enhancing the tensile properties of the material. Thus, the high melt strength tensile polyethylene possesses both high melt strength and tensile strength. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 These are comparison images of the electron scanning morphology of polyethylene prepared in the embodiments and comparative examples of the present invention. Detailed Implementation

[0028] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0029] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available or self-made conventional reagents or instruments.

[0030] Sources of main raw materials in the examples and comparative examples Wanhua Chemical Co., Ltd., high-density polyethylene, grade 23050; Exxon Corporation, metallocene polyethylene, grade 2010; Ethylene-octene block copolymer, Dow Chemical, grade 9010; Ethylene-octene copolymer, Wanhua Chemical, grade 65056; Dicyclic [2.2.1]heptan-2,3-dicarboxylic acid disodium Milliken, HPN-68; Antioxidant Maclean, brand names 1010, 168, and 1024; Poly(3-methyl-1-butene), degree of polymerization 600-1500.

[0031] Example 1 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 15 parts metallocene polyethylene, 15 parts ethylene-octene block copolymer (OBC), 5 parts composite additive (dicycloheptan-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene in a mass ratio of 5:5), 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168 and 0.1 parts antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0032] Example 2 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 15 parts metallocene polyethylene, 15 parts ethylene-octene copolymer (POE), 5 parts composite additive (the mass ratio of disodium dicycloheptan-2,3-dicarboxylate and poly-3-methyl-1-butene is 5:5), 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168 and 0.1 parts antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0033] Example 3 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 20 parts metallocene polyethylene, 20 parts ethylene-octene block copolymer (OBC), 5 parts composite additive (the mass ratio of dicycloheptan-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene is 5:5), 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168, and 0.1 parts antioxidant 1024.

[0034] The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0035] Example 4 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight, 50 parts of high-density polyethylene, 20 parts of metallocene polyethylene, 20 parts of ethylene-octene block copolymer (OBC), 7 parts of composite additives (the mass ratio of dicycloheptan-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene is 5:5), 0.1 parts of antioxidant 1010, 0.1 parts of antioxidant 168, and 0.1 parts of antioxidant 1024.

[0036] The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0037] Example 5 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 20 parts metallocene polyethylene, 20 parts ethylene-octene block copolymer (OBC), 2 parts composite additive (the mass ratio of dicycloheptan-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene is 5:5), 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168, and 0.1 parts antioxidant 1024.

[0038] The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0039] Comparative Example 1 This comparative example provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight, 50 parts of high-density polyethylene, 0.1 parts of antioxidant 1010, 0.1 parts of antioxidant 168 and 0.1 parts of antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0040] Comparative Example 2 This comparative example provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight, 50 parts of high-density polyethylene, 15 parts of metallocene polyethylene, 15 parts of ethylene-octene block copolymer (OBC), 0.1 parts of antioxidant 1010, 0.1 parts of antioxidant 168 and 0.1 parts of antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0041] Comparative Example 3 This comparative example provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight, 50 parts of high-density polyethylene, 20 parts of metallocene polyethylene, 20 parts of ethylene-octene block copolymer (OBC), 0.1 parts of antioxidant 1010, 0.1 parts of antioxidant 168 and 0.1 parts of antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0042] Comparative Example 4 This comparative example provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight, 50 parts of high-density polyethylene, 15 parts of ethylene-octene block copolymer (OBC), 5 parts of composite additive (the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly3-methyl-1-butene is 5:5), 0.1 parts of antioxidant 1010, 0.1 parts of antioxidant 168 and 0.1 parts of antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0043] Comparative Example 5 This comparative example provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 15 parts metallocene polyethylene, 5 parts composite additive (the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene is 5:5), 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168 and 0.1 parts antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0044] Comparative Example 6 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 15 parts metallocene polyethylene, 15 parts ethylene-octene block copolymer (OBC), 5 parts disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate, 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168 and 0.1 parts antioxidant 1024; The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0045] Comparative Example 7 This embodiment provides a method for preparing high melt strength tensile polyethylene, the raw materials of which include, by weight: 50 parts high-density polyethylene, 15 parts metallocene polyethylene, 15 parts ethylene-octene block copolymer (OBC), 5 parts poly-3-methyl-1-butene, 0.1 parts antioxidant 1010, 0.1 parts antioxidant 168 and 0.1 parts antioxidant 1024.

[0046] The preparation process is carried out in a twin-screw extruder. The structure and function of the twin-screw extruder are as follows: the extruder used is a co-rotating twin-screw extruder, which includes 10 heating and temperature control zones. Natural venting is performed in the fifth section of the extruder, and forced vacuum venting is performed in the ninth section. The preparation method involves mixing the raw materials evenly and then adding them to a twin-screw extruder for melt reaction, extrusion, and granulation to obtain high melt strength tensile polyethylene. The screw speed is controlled at 350 r / min, and the heating temperatures of each section of the extruder are: 135℃, 150℃, 170℃, 185℃, 190℃, 200℃, 200℃, 195℃, 195℃, 195℃.

[0047] Test case Melt strength (MS) was measured using a Rhedtens (Gottfert, Germany) melt strength tester with a roller rotation acceleration of 20 mm / s². Melt flow rate (MFR) was measured according to the relevant ASTM standards. Tensile strength was tested according to GB1040-2006. The test results are shown in Table 1. Table 1

[0048] The 4904 / 4904LS samples in Table 1 are polyethylene products from Basel.

[0049] Comparative Examples 1, 2, and 3 conclude that without the addition of composite additives, increasing the proportion of metallocene and toughening agents yields almost no improvement in the tensile properties and melt strength of the material. Comparative Examples 6 and 7 show that adding only one component of the composite additive provides limited improvement in tensile strength. However, the blend material prepared by mixing the two components exhibits significantly improved tensile strength, and its melt strength is also superior to that of the single component. Figure 1 To observe the results using scanning electron microscopy, surface cracks in A (Comparative Example 2) were long and deep, indicating moderate compatibility. C and B (Comparative Example 6) still had many cracks, but cracks in D (Example 1) almost disappeared, crystal nuclei increased, and rigidity was enhanced. The two components in the composite additive can play a synergistic role, reducing the tension of the blended components, improving compatibility, and changing the crystallization properties of the entire blend system, thereby obtaining high melt strength tensile polyethylene through the blending process.

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A high melt strength tensile polyethylene, characterized in that, By weight, the raw materials include 30-60 parts high-density polyethylene, 10-35 parts metallocene polyethylene, 15-25 parts toughening agent, 2-7 parts composite additive, and 0.1-0.3 parts antioxidant. The composite additive is composed of disodium bicyclo[2.2.1]heptane-2,3-dicarboxylic acid and poly3-methyl-1-butene.

2. The high melt strength tensile polyethylene according to claim 1, characterized in that, The density of the high-density polyethylene is 0.945 g / cm³. 3 ~0.955g / cm 3 The melt index (190℃ / 5kg) is 0.22-0.25g / 10min, and the weight-average molecular weight is 2.5x10. 5 -2.7x10 5 g / mol; Preferably, the density of the high-density polyethylene is 0.950 g / cm³. 3 The melt index (190℃ / 5kg) is 0.23g / 10min, and the weight-average molecular weight is 2.67x10. 5 g / mol; Preferably, the high-density polyethylene is Wanhua 23050.

3. The high melt strength tensile polyethylene according to claim 1 or 2, characterized in that, The density of the metallocene catalyst is 0.910 g / cm³. 3 ~0.930 cm 3 The melt index (190℃ / 2.16kg) is 0.8-1.1g / 10min.

4. The high melt strength tensile polyethylene according to any one of claims 1-3, characterized in that, The toughening agent includes at least one of ethylene-octene block copolymer and ethylene-octene copolymer.

5. The high melt strength tensile polyethylene according to any one of claims 1-4, characterized in that, The antioxidants include at least two of the following: hindered phenolic antioxidants, phosphorous antioxidants, and aromatic amine antioxidants.

6. The high melt strength tensile polyethylene according to any one of claims 1-5, characterized in that, The degree of polymerization of poly(3-methyl-1-butene) is 600-1500; Preferably, the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly3-methyl-1-butene is (4.5-5.5):(4.5-5.5). Preferably, the mass ratio of dicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt and poly-3-methyl-1-butene is 5:

5.

7. The high melt strength tensile polyethylene according to any one of claims 1-6, characterized in that, The high melt strength tensile polyethylene has a melt strength of 0.25-0.6 N and a tensile strength of 25-41 MPa.

8. A method for preparing high melt strength tensile polyethylene according to any one of claims 2-7, characterized in that, The raw materials are mixed and then melted, followed by extrusion and granulation to obtain the high melt strength tensile polyethylene.

9. The preparation method according to claim 8, characterized in that, The melting reaction, extrusion, and granulation are carried out in a twin-screw extruder.

10. The application of high melt strength tensile polyethylene according to any one of claims 1-7 or high melt strength tensile polyethylene prepared by the preparation method according to claim 8 or 9 in extrusion coating, blow molding, profile extrusion, and thermoforming.

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