Polyethylene resin and preparation method thereof

Abstract

The invention relates to the technical field of polyethylene resin, in particular to polyethylene resin and a preparation method thereof. The polyethylene resin comprises the following raw materials in parts by weight: 80-100 parts of linear low-density polyethylene, 30-40 parts of low-density high-pressure polyethylene, 6-10 parts of an initiator, 6-10 parts of a functional aid, 4-6 parts of an additive, 4-6 parts of a catalyst, 4-6 parts of a comonomer and 2-4 parts of an antioxidant. According to the invention, the compound of tannic acid and protein can interact with a polyethylene resin molecular chain, a phenolic hydroxyl group in a tannic acid molecule can form a hydrogen bond with an active site on the polyethylene resin molecular chain, and a peptide chain in a protein molecule can be wound on the resin molecular chain; a reinforced network is constructed in the polyethylene resin by utilizing the interaction of tannic acid and protein, and when the material is subjected to a tensile force, the stress can be effectively transferred and dispersed, so that the tensile strength of the resin is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyethylene resins, and specifically to a polyethylene resin and a preparation method thereof. Background Art

[0002] Polyethylene resin is a thermoplastic resin prepared by polymerizing ethylene monomers. It has excellent low-temperature resistance and good chemical stability. Since the polymer molecules are connected by carbon-carbon single bonds, it can resist the erosion of most acids and bases, is insoluble in general solvents at room temperature, has low water absorption, and excellent electrical insulation.

[0003] In the prior art, low-density polyethylene is produced by free radical polymerization under high temperature and high pressure conditions. This polymerization method makes the molecular chains contain more long and short branches, making it difficult to form a regular and tight crystalline structure between the molecular chains, which affects the structural strength of the polyethylene resin. Based on this, the present invention provides a polyethylene resin and a preparation method thereof. Summary of the Invention

[0004] The purpose of the present invention is to provide a polyethylene resin and a preparation method thereof. The polyethylene resin prepared by the present invention not only has good tensile yield strength performance, but also has excellent flexural modulus performance, effectively improving the use performance of the polyethylene resin.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: In the first aspect, the present invention provides a polyethylene resin, which comprises the following raw materials in parts by weight: 80-100 parts of linear low-density polyethylene, 30-40 parts of low-density high-pressure polyethylene, 6-10 parts of initiator, 6-10 parts of functional auxiliary agent, 4-6 parts of additive, 4-6 parts of catalyst, 4-6 parts of comonomer and 2-4 parts of antioxidant.

[0006] Further, the initiator is selected from at least one of benzoyl peroxide and azobisisobutyronitrile, and the catalyst is selected from at least one of titanium tetrachloride and triethylaluminum.

[0007] Further, the comonomer is selected from at least one of 1-butene, 1-hexene and 1-octene.

[0008] Further, the antioxidant is selected from at least one of pentaerythritol ester of rosin, phosphite and 3,5-di-tert-butyl.

[0009] Further, the functional auxiliary agent is prepared by the following method: mix pelletierine with soy protein, the mass ratio of pelletierine to soy protein is 1:(0.4-0.6), heat the mixture in a water bath to 60-80 °C, continuously stir during the water bath heating process, and then obtain the functional auxiliary agent through static cooling and filtration.

[0010] Further, the pelletierine is prepared by the following method: Recycling pomegranate peel waste as raw material in a juice factory, spreading the pomegranate peel flat to dry, then performing crushing and grinding treatments to obtain pomegranate peel powder. Mix the pomegranate peel powder with deionized water, and the mass ratio of the pomegranate peel powder to deionized water is 1:(8 - 10). After mixing, add cellulase, and the mass of the cellulase is 20 - 30% of the pomegranate peel powder. Continue to mix and then heat in a water bath to 40 - 50°C, then let it stand for 2 - 4 h to obtain a suspension. Transfer the suspension to an ultrasonic device and process it under the condition of 60 - 80 kHz for 12 - 18 min, then perform filtration, washing, and drying treatments to obtain pelletierine.

[0011] Further, the soy protein is prepared by the following method: Select low-temperature defatted soybean meal as raw material, perform grinding treatment on the raw material, then mix the low-temperature defatted soybean meal with an alkali solution, and the mass of the alkali solution is 16 - 20% of the mass of the low-temperature defatted soybean meal. Place the mixture of the low-temperature defatted soybean meal and the alkali solution in an alkali dissolution tank, set the temperature at 40 - 60°C, pH value at 7.4 - 7.8, stirring speed at 120 - 140 r / min, and treatment time at 25 - 35 min. Then transfer the mixture of the low-temperature defatted soybean meal and the alkali solution to a centrifuge, set it at 2400 - 2800 r / min for 4 - 8 min. After centrifugation, remove the supernatant and retain the precipitate, and perform washing and drying treatments on the precipitate to obtain soy protein.

[0012] Further, the additive is prepared by the following method: Select rosin and starch as raw materials, and the mass ratio of rosin to starch is 1:(0.4 - 0.6). Place the starch in an oven and set it at 60 - 70°C for drying treatment for 2 - 4 h. Mix the starch with water for dissolution to obtain starch water, and the mass of the water is 2 - 3 times the mass of the starch. After mixing, add rosin to the starch water, heat in a water bath to 85 - 95°C, and keep stirring for 10 - 16 min to obtain the additive.

[0013] Further, the rosin is selected as rosin resin, and the starch is selected as potato starch.

[0014] In the second aspect, the present invention provides a preparation method of polyethylene resin, including the following steps: Weigh each raw material as needed and place it in a mixer, set the mixing speed at 200 - 300 r / min for mixing treatment for 20 - 30 min. After mixing, add the raw materials into a twin-screw granulator, set the temperature at 180 - 200°C, and perform cutting treatment after cooling to obtain polyethylene resin.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the present invention, during the preparation process of polyethylene resin, by adding functional additives, the pelletierine contained in the functional additives reacts with soy protein. Among them, the addition of pelletierine can adsorb onto the resin molecular chains, providing nucleation sites for crystallization, making the crystallization of polyethylene resin more compact, enhancing the structural strength of polyethylene resin. Utilizing the thermal denaturation of soy protein, it can form aggregates with the resin molecular chains, restricting the excessive movement of the resin molecular chains at high temperatures, thereby improving the structural stability of the polyethylene resin after thermoforming.

[0016] 2. In the present invention, by utilizing the large amount of tannic acid contained in pelletierine, the tannic acid combines with the protein in soy protein during the preparation process. The complex of tannic acid and protein can interact with the polyethylene resin molecular chains. Among them, the phenolic hydroxyl groups in the tannic acid molecules can form hydrogen bonds with the active sites on the polyethylene resin molecular chains, and the peptide chains in the protein molecules can wind around the resin molecular chains. By using the interaction between tannic acid and protein, a reinforcement network is constructed inside the polyethylene resin. When the material is subjected to tensile force, it can effectively transfer and disperse stress, thereby improving the tensile strength of the resin.

[0017] 3. In the present invention, during the preparation process of polyethylene resin, by adding additives, after adding rosin in the additives, using the abietic acid component in rosin, which contains carboxyl and double bond active groups, it can interact with the active sites on the polyethylene molecular chains, further enhancing the structural strength of polyethylene resin.

[0018] 4. In the additives, through the binding reaction between rosin and starch, the hydroxyl groups of starch can undergo an esterification reaction with the carboxyl groups in rosin under high temperature. During the cross-linking process, the phenolic hydroxyl groups in the molecular structures of rosin and starch can capture free radicals, reducing the contact between oxygen and polyethylene resin, delaying the oxidative degradation process of polyethylene resin, and enhancing the service life of polyethylene resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a flowchart of a polyethylene resin and its preparation method proposed by the invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0022] A polyethylene resin comprises the following raw materials in parts by weight: 80-100 parts of linear low density polyethylene, 30-40 parts of low density high pressure polyethylene, 6-10 parts of initiator, 6-10 parts of functional auxiliary agent, 4-6 parts of additive, 4-6 parts of catalyst, 4-6 parts of comonomer and 2-4 parts of antioxidant.

[0023] In some embodiments, the initiator is selected from at least one of benzoyl peroxide and azobisisobutyronitrile, and the catalyst is selected from at least one of titanium tetrachloride and triethylaluminum.

[0024] In some embodiments, the comonomer is selected from at least one of 1-butene, 1-hexene and 1-octene.

[0025] In some embodiments, the antioxidant is selected from at least one of pentaerythritol ester of rosin, phosphite and 3,5-di-tert-butyl.

[0026] In some embodiments, the functional auxiliary agent is prepared by the following method: pelletierine is mixed with soy protein, and the mass ratio of pelletierine to soy protein is 1:(0.4-0.6). After mixing, it is heated in a water bath to 60-80 °C, and stirring is continuously maintained during the water bath heating process. Then, after standing and cooling and filtration treatment, the functional auxiliary agent is obtained.

[0027] In this embodiment, by adding the functional auxiliary agent during the preparation of the polyethylene resin, the pelletierine contained in the functional auxiliary agent acts in combination with soy protein. Utilizing the thermal denaturation of soy protein, a condensate can be formed with the resin molecular chain, restricting the excessive movement of the resin molecular chain at high temperature, thereby improving the structural stability of the polyethylene resin after thermoforming. By using a large amount of tannic acid contained in pelletierine, the tannic acid combines with the protein in soy protein during the preparation process. The complex of tannic acid and protein can interact with the polyethylene resin molecular chain. Among them, the phenolic hydroxyl group in the tannic acid molecule can form a hydrogen bond with the active site on the polyethylene resin molecular chain, and the peptide chain in the protein molecule can wind around the resin molecular chain. An enhanced network is constructed inside the polyethylene resin by utilizing the interaction between tannic acid and protein. When the material is subjected to a tensile force, the stress can be effectively transmitted and dispersed, thereby improving the tensile strength of the resin.

[0028] In some embodiments, pelletierine is prepared by the following method: Recover pomegranate peel waste as raw material in a juice factory, lay the pomegranate peel flat to dry, then crush and grind it to obtain pomegranate peel powder. Mix the pomegranate peel powder with deionized water, with the mass ratio of pomegranate peel powder to deionized water being 1:(8 - 10). After mixing, add cellulase, and the mass of cellulase is 20 - 30% of the pomegranate peel powder. Continue to mix and then heat in a water bath to 40 - 50 °C, and then let it stand for 2 - 4 h to obtain a suspension. Transfer the suspension to an ultrasonic device and process it for 12 - 18 min under the condition of 60 - 80 kHz, and then perform filtration, washing, and drying treatments to obtain pelletierine.

[0029] In this embodiment, the addition of pelletierine can adsorb to the resin molecular chain, provide nucleation sites for crystallization, make the crystallization of polyethylene resin more compact, and improve the structural strength of polyethylene resin.

[0030] In some embodiments, soy protein is prepared by the following method: Select low-temperature defatted soybean meal as raw material, grind the raw material, and then mix the low-temperature defatted soybean meal with an alkali solution. The mass of the alkali solution is 16 - 20% of the mass of the low-temperature defatted soybean meal. Place the mixture of low-temperature defatted soybean meal and alkali solution in an alkali dissolution tank, set the temperature at 40 - 60 °C, the pH value at 7.4 - 7.8, the stirring speed at 120 - 140 r / min, and the treatment time at 25 - 35 min. Then transfer the mixture of low-temperature defatted soybean meal and alkali solution to a centrifuge, set it at 2400 - 2800 r / min and process for 4 - 8 min. After centrifugation, remove the supernatant and retain the precipitate, and perform washing and drying treatments on the precipitate to obtain soy protein.

[0031] In this embodiment, by utilizing the thermal denaturation of soy protein, it can form aggregates with the resin molecular chain, restrict the excessive movement of the resin molecular chain at high temperatures, and thus improve the structural stability of the polyethylene resin after thermoforming.

[0032] In some embodiments, the additive is prepared by the following method: Select rosin and starch as raw materials, with the mass ratio of rosin to starch being 1:(0.4 - 0.6). Place the starch in an oven and set it at 60 - 70 °C for drying treatment for 2 - 4 h. Mix the starch with water for dissolution to obtain starch water, and the mass of water is 2 - 3 times the mass of the starch. After mixing, add rosin to the starch water, heat in a water bath to 85 - 95 °C, and keep stirring for 10 - 16 min to obtain the additive.

[0033] In this embodiment, by adding additives during the preparation of polyethylene resin, after the rosin in the additives is added, using the abietic acid component in the rosin, the abietic acid contains carboxyl and double bond active groups, which can interact with the active sites on the polyethylene molecular chain, further enhancing the structural strength of the polyethylene resin. In the additives, through the binding reaction of rosin and starch, the hydroxyl group of starch can react with the carboxyl group in rosin under high temperature to undergo an esterification reaction. During the cross-linking process, the phenolic hydroxyl groups in the molecular structures of rosin and starch can capture free radicals, reduce the contact between oxygen and the polyethylene resin, delay the oxidative degradation process of the polyethylene resin, and improve the service life of the polyethylene resin.

[0034] In some embodiments, rosin resin is selected as the rosin, and potato starch is selected as the starch.

[0035] In some embodiments, a method for preparing a polyethylene resin includes the following steps: Weigh each raw material as needed and place it in a mixer, set the mixing speed at 200 - 300 r / min for 20 - 30 min. After mixing, add the raw materials into a twin-screw granulator, set the temperature at 180 - 200 °C, and after granulation, perform cutting treatment after cooling to obtain the polyethylene resin.

[0036] In this embodiment, an enhanced network is constructed inside the polyethylene resin by using the interaction between tannic acid and protein. When the material is subjected to a tensile force, the stress can be effectively transmitted and dispersed, thereby improving the tensile strength of the resin.

[0037] Based on the foregoing embodiments, the inventor also conducted the following multiple groups of experiments: It should be noted that the raw materials used in the following experiments are all commercially available raw materials.

[0038] Experiment 1: Preparation of pelletierine: Spread pomegranate peel flat to dry, then crush and grind it to obtain pomegranate peel powder. Mix the pomegranate peel powder with deionized water, and the mass ratio of pomegranate peel powder to deionized water is 1:8. After mixing, add cellulase, and the mass of cellulase is 20% of the pomegranate peel powder. Continue to mix and heat in a water bath to 40 °C, then let it stand for 2 h to obtain a suspension. Transfer the suspension to an ultrasonic device and process it for 12 min under the condition of 60 kHz, and then perform filtration, washing, and drying treatments; Soybean protein preparation: Select low-temperature defatted soybean meal as the raw material, grind the raw material, and then mix the low-temperature defatted soybean meal with lye. The mass of the lye is 16% of the mass of the low-temperature defatted soybean meal. Place the mixture of the low-temperature defatted soybean meal and lye in an alkali dissolution tank, set the temperature at 40 °C, the pH value at 7.4, the stirring speed at 120 r / min, and the treatment time at 25 min. Then transfer the mixture of the low-temperature defatted soybean meal and lye to a centrifuge, set it at 2400 r / min for 4 min. After centrifugation, remove the supernatant and retain the precipitate. Wash and dry the precipitate; Functional adjuvant preparation: Mix pelletierine with soybean protein. The mass ratio of pelletierine to soybean protein is 1:0.4. After mixing, heat it in a water bath to 60 °C and continuously stir during the water bath heating process. Then let it stand and cool, and filter it; Additive preparation: Select rosin and starch as raw materials. The rosin is selected as rosin resin, and the starch is selected as potato starch. The mass ratio of rosin to starch is 1:0.4. Place the starch in an oven and set it at 60 °C for drying treatment for 2 h. Mix the starch with water for dissolution to obtain starch water. The mass of water is twice the mass of the starch. After mixing, add rosin to the starch water and heat it in a water bath to 85 °C, and keep stirring for 10 min; Raw material preparation: 80 parts of linear low-density polyethylene, 30 parts of low-density high-pressure polyethylene, 6 parts of initiator, 6 parts of functional adjuvant, 4 parts of additive, 4 parts of catalyst, 4 parts of comonomer, and 2 parts of antioxidant. Among them, the initiator is selected as dibenzoyl peroxide, the catalyst is selected as titanium tetrachloride, the comonomer is selected as 1-butene, and the antioxidant is selected as rosin pentaerythritol ester; Polyethylene resin preparation: Weigh each raw material as needed and place it in a mixer, set it at 200 r / min for mixing treatment for 20 min. After mixing, add the raw materials to a twin-screw granulator, set the temperature at 180 °C, and after granulation, cool and cut the materials.

[0039] Experiment 2: Pelletierine preparation: Spread the pomegranate peel out to dry, and then crush and grind it to obtain pomegranate peel powder. Mix the pomegranate peel powder with deionized water. The mass ratio of the pomegranate peel powder to deionized water is 1:9. After mixing, add cellulase. The mass of the cellulase is 25% of the mass of the pomegranate peel powder. Continue to mix and heat it in a water bath to 45 °C, then let it stand for 3 h to obtain a suspension. Transfer the suspension to an ultrasonic device and process it under the condition of 70 kHz for 14 min. Then filter, wash, and dry it; Soybean protein preparation: Select low-temperature defatted soybean meal as the raw material, grind the raw material, and then mix the low-temperature defatted soybean meal with lye. The mass of the lye is 18% of the mass of the low-temperature defatted soybean meal. Place the mixture of the low-temperature defatted soybean meal and lye in an alkali dissolution tank, set the temperature at 40 °C, the pH value at 7.4, the stirring speed at 130 r / min, and the treatment time at 30 min. Then transfer the mixture of the low-temperature defatted soybean meal and lye to a centrifuge, set it at 2600 r / min for 6 min, remove the supernatant after centrifugation, retain the precipitate, and wash and dry the precipitate; Functional adjuvant preparation: Mix pelletierine with soybean protein. The mass ratio of pelletierine to soybean protein is 1:0.5. After mixing, heat it in a water bath to 70 °C, and keep stirring continuously during the water bath heating process. Then let it stand and cool, and filter it; Additive preparation: Select rosin and starch as the raw materials. The rosin is selected as rosin resin, and the starch is selected as potato starch. The mass ratio of rosin to starch is 1:0.5. Place the starch in an oven and set it at 65 °C for drying treatment for 3 h. Mix the starch with water for dissolution to obtain starch water. The mass of water is 2.5 times the mass of the starch. After mixing, add rosin to the starch water, heat it in a water bath to 90 °C, and keep stirring for 13 min; Raw material preparation: 90 parts of linear low-density polyethylene, 35 parts of low-density high-pressure polyethylene, 8 parts of initiator, 8 parts of functional adjuvant, 5 parts of additive, 5 parts of catalyst, 5 parts of comonomer, and 3 parts of antioxidant. Among them, the initiator is selected as azobisisobutyronitrile, the catalyst is selected as triethylaluminum, the comonomer is selected as 1-hexene, and the antioxidant is selected as phosphite; Polyethylene resin preparation: Weigh each raw material as needed and place it in a mixer, set it at 250 r / min for mixing treatment for 25 min. After mixing, add the raw materials to a twin-screw granulator, set the temperature at 190 °C, and perform cutting treatment after granulation and cooling.

[0040] Experiment Three: Pelletierine preparation: Spread the pomegranate peel out to dry, and then perform crushing and grinding treatments to obtain pomegranate peel powder. Mix the pomegranate peel powder with deionized water. The mass ratio of the pomegranate peel powder to deionized water is 1:10. After mixing, add cellulase. The mass of the cellulase is 30% of the mass of the pomegranate peel powder. Continue to mix and then heat it in a water bath to 50 °C. Then let it stand for 4 h to obtain a suspension. Transfer the suspension to an ultrasonic device and treat it under the condition of 80 kHz for 18 min. Then perform filtration, washing, and drying treatments; Soybean protein preparation: Select low-temperature defatted soybean meal as the raw material, grind the raw material, and then mix the low-temperature defatted soybean meal with alkali solution. The mass of the alkali solution is 20% of the mass of the low-temperature defatted soybean meal. Place the mixture of low-temperature defatted soybean meal and alkali solution in an alkali dissolution tank, set the temperature at 60°C, pH value at 7.8, stirring speed at 140 r / min, and treatment time at 35 min. Then transfer the mixture of low-temperature defatted soybean meal and alkali solution to a centrifuge, set it at 2800 r / min for 8 min, remove the supernatant after centrifugation, retain the precipitate, and wash and dry the precipitate; Functional adjuvant preparation: Mix pelletierine with soybean protein, and the mass ratio of pelletierine to soybean protein is 1:0.6. After mixing, heat it in a water bath to 80°C, and keep stirring continuously during the water bath heating process. Then let it stand and cool, and filter it; Additive preparation: Select rosin and starch as raw materials. For rosin, choose rosin resin, and for starch, choose potato starch. The mass ratio of rosin to starch is 1:0.6. Place the starch in an oven and set it at 70°C for drying treatment for 4 h. Mix the starch with water for dissolution to obtain starch water. The mass of water is 3 times the mass of the starch. After mixing, add rosin to the starch water, heat it in a water bath to 95°C, and keep stirring for 16 min; Raw material preparation: 100 parts of linear low-density polyethylene, 40 parts of low-density high-pressure polyethylene, 10 parts of initiator, 10 parts of functional adjuvant, 6 parts of additive, 6 parts of catalyst, 6 parts of comonomer, and 4 parts of antioxidant. Among them, the initiator is selected as benzoyl peroxide, the catalyst is selected as titanium tetrachloride, the comonomer is selected as 1-octene, and the antioxidant is selected as 3,5-di-tert-butyl; Polyethylene resin preparation: Weigh each raw material as needed and place it in a mixer, set it at 300 r / min for mixing treatment for 30 min. After mixing, add the raw materials to a twin-screw granulator, set the temperature at 200°C, and after granulation, cool and cut the materials.

[0041] Comparative example 1. The difference between this comparative example and Experimental example 1 is that: This comparative example does not contain functional adjuvant.

[0042] Comparative example 2. The difference between this comparative example and Experimental example 1 is that: This comparative example does not contain additive.

[0043] Comparative example 3. The difference between this comparative example and Experimental example 1 is that: In this comparative example, an equal amount of rosin is used to replace the additive.

[0044] Comparative example 4. The difference between this comparative example and Experimental example 1 is that: In this comparative example, an equal amount of soybean protein is used to replace the functional adjuvant.

[0045] Performance test: The polyethylene resins prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were subjected to performance tests, and the obtained test data were recorded in the following table:

[0046] In the performance test, the tensile yield strength test was carried out with reference to GB1040-2-2006, and the flexural modulus test was carried out with reference to GB9341-2008.

[0047] Among them, the tensile yield strength test results of the polyethylene resins prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were 12.3 MPa, 11.4 MPa, 12.2 MPa, 6.5 MPa, 6.9 MPa, 7.4 MPa and 8.1 MPa respectively; The flexural modulus test results of the polyethylene resins prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were 256 MPa, 241 MPa, 251 MPa, 167 MPa, 171 MPa, 183 MPa and 194 MPa respectively.

[0048] It can be seen that the tensile yield strength performance and flexural modulus performance of the polyethylene resins prepared in Comparative Examples 1, 2, 3 and 4 are both lower than those in Experiments 1, 2 and 3; this shows that: by adding functional additives in the process of preparing polyethylene resin, the pelletierine contained in the functional additives acts in combination with soy protein. Among them, the addition of pelletierine can adsorb on the resin molecular chain, providing nucleation sites for crystallization, making the crystallization of polyethylene resin more compact, improving the structural strength of polyethylene resin. Utilizing the thermal denaturation of soy protein, it can form aggregates with the resin molecular chain, restricting the excessive movement of the resin molecular chain at high temperature, thereby improving the structural stability of the polyethylene resin after thermoforming. The phenolic hydroxyl groups in tannic acid molecules can form hydrogen bonds with the active sites on the polyethylene resin molecular chain, and the peptide chains in protein molecules can wind around the resin molecular chain. By utilizing the interaction between tannic acid and protein, a reinforcing network is constructed inside the polyethylene resin. When the material is subjected to tensile force, the stress can be effectively transmitted and dispersed, thereby improving the tensile strength of the resin.

[0049] By comparing and analyzing the relevant data in the table, it can be known that the polyethylene resin prepared by the present invention not only has good tensile yield strength performance, but also has excellent flexural modulus performance. This shows that the polyethylene resin and its preparation method provided by the present invention have a broader market prospect and are more suitable for promotion.

[0050] In the description of this specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A polyethylene resin, characterized in that: The invention comprises the following raw materials in parts by weight: 80 to 100 parts of linear low-density polyethylene, 30 to 40 parts of low-density high-pressure polyethylene, 6 to 10 parts of initiator, 6 to 10 parts of functional additive, 4 to 6 parts of additive, 4 to 6 parts of catalyst, 4 to 6 parts of comonomer and 2 to 4 parts of antioxidant.

2. The polyethylene resin according to claim 1, characterized in that The initiator is selected from at least one of dibenzoyl peroxide and azobisisobutyronitrile, and the catalyst is selected from at least one of titanium tetrachloride and triethylaluminum.

3. The polyethylene resin according to claim 1, characterized in that The comonomer is at least one of 1-butene, 1-hexene and 1-octene.

4. The polyethylene resin according to claim 1, characterized in that The antioxidant is selected from at least one of rosin pentaerythritol ester, phosphite and 3,5-di-tert-butyl.

5. The polyethylene resin according to claim 1, characterized in that The functional additive is prepared by the following method: pomegranate peel alkali and soybean protein are mixed, the mass ratio of pomegranate peel alkali to soybean protein is 1: (0.4-0.6), the mixture is heated in a water bath to 60-80°C, stirring is continuously maintained during the water bath heating process, and then the functional additive is prepared through standing cooling and filtering.

6. The polyethylene resin according to claim 5, characterized in that The pomegranate peel alkali is prepared by the following method: pomegranate peel waste is recovered as a raw material from a juice factory, the pomegranate peel is spread flat and dried, and then crushed and ground to obtain pomegranate peel powder, the pomegranate peel powder is mixed with deionized water, the mass ratio of the pomegranate peel powder to the deionized water is 1: (8-10), cellulase is added after mixing, and the mass of the cellulase is 20-30% of the pomegranate peel powder, the mixing is continued, and the water bath is heated to 40-50° C., and then the suspension is allowed to stand for 2-4 hours to obtain a suspension, the suspension is transferred to an ultrasonic device, and the suspension is treated for 12-18 minutes under the condition of 60-80kHz, and then filtered, washed, and dried to obtain pomegranate peel alkali.

7. The polyethylene resin according to claim 5, characterized in that The soy protein is prepared by the following method: low-temperature defatted soybean meal is selected as a raw material, the raw material is ground, and then the low-temperature defatted soybean meal is mixed with alkali solution, the mass of the alkali solution is 16-20% of the mass of the low-temperature defatted soybean meal, the low-temperature defatted soybean meal and the alkali solution mixture is placed in an alkali dissolving tank, the temperature is set at 40-60°C, the pH value is 7.4-7.8, the stirring speed is 120-140r / min, the processing time is 25-35min, and then the low-temperature defatted soybean meal and the alkali solution mixture is transferred to a centrifuge, set at 2400-2800r / min for processing for 4-8min, remove the supernatant after centrifugation, retain the precipitate, wash and dry the precipitate to prepare the soy protein.

8. The polyethylene resin according to claim 1, characterized in that The additive is prepared by the following method: rosin and starch are selected as raw materials, the mass ratio of rosin to starch is 1: (0.4-0.6), the starch is placed in an oven set at 60-70°C for drying for 2-4 hours, the starch is mixed with water for dissolution to obtain starch water, the mass of the water is 2-3 times the mass of the starch, rosin is added to the starch water after mixing, the water is heated to 85-95°C in a water bath, and the mixture is stirred for 10-16 minutes to obtain the additive.

9. The polyethylene resin according to claim 8, characterized in that The rosin is selected from rosin resin, and the starch is selected from potato starch.

10. A method for preparing a polyethylene resin according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: weighing various raw materials as required and placing them in a mixer, setting the speed at 200-300 r / min for mixing for 20-30 minutes, adding the raw materials into a twin-screw granulator after mixing, setting the temperature at 180-200° C., cooling after granulation, and cutting the materials to obtain polyethylene resin.

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