Polyethylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a polyethylene composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The polyethylene composite material comprises the following components in parts by weight: 100 parts of high-density polyethylene, 6-20 parts of a high-density polyethylene reclaimed material, 3-16 parts of ultra-high molecular weight polyethylene, 1-6 parts of a compatilizer, 1-2 parts of an inorganic filler and 1-2 parts of a flow modifier, 2-3 parts of color master batch; wherein the viscosity average relative molecular weight of the ultra-high molecular weight polyethylene is 1,000,000-2,000,000, and the test standard is ASTM (American Society for Testing Material) D4020. According to the polyethylene composite material disclosed by the invention, part of the high-density polyethylene recycled material is doped, and the interface bonding force between the new high-density polyethylene material and the high-density polyethylene recycled material is improved through the synergistic effect of the ultra-high molecular weight polyethylene, the compatilizer and the inorganic filler; the mechanical property and the wear-resisting property of the polyethylene composite material doped with the high-density polyethylene reclaimed material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically, to a polyethylene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polyethylene double-wall corrugated pipe is a kind of pipe made of high-density polyethylene (HDPE) by an extrusion molding process. Its structural characteristics are that the inner wall is smooth and the outer wall is annularly corrugated. The double-wall design improves the ring stiffness and the ability to resist external pressure. At the same time, it has the characteristics of light weight, corrosion resistance, low temperature resistance, and long service life. This kind of pipe is widely used in buried non-pressure drainage and sewage systems, and has low requirements for the appearance and hydrostatic pressure of the pipe. Therefore, when producing polyethylene double-wall corrugated pipes, it is usually allowed to incorporate a certain proportion of polyethylene recycled materials. It is reported that the global annual plastic waste exceeds 300 million tons, but the recovery rate is less than 10%. Among them, polyethylene plastics are difficult to degrade due to their strong chemical stability, becoming a difficult point in environmental governance. Incorporating a certain proportion of polyethylene recycled materials into polyethylene double-wall corrugated pipes has double economic and environmental benefits.

[0003] A Chinese patent discloses a modified HDPE double-wall corrugated pipe and a manufacturing method thereof. The mass fractions of the materials used for the modified HDPE double-wall corrugated pipe are as follows: 100-120 parts of HDPE, 30-40 parts of HDPE recycled material, 15-25 parts of modified ultrafine glass microspheres, 5-10 parts of coupling agent, and 5-10 parts of lubricant. Outer layer: 100-120 parts of HDPE, 15-25 parts of modified ultrafine glass microspheres, 5-10 parts of coupling agent, and 5-10 parts of lubricant. Although the above-disclosed technology realizes the reuse of recycled materials, due to the fact that the performance of polyethylene recycled materials is worse than that of new materials, the introduction of recycled materials will cause the key performance of polyethylene double-wall corrugated pipes to decay. The main manifestations are as follows: (1) The ring stiffness of the pipe decreases compared with that of the pure new material product due to the molecular chain breakage and thermal aging of the recycled material, and it is difficult to meet the requirements of the buried project for the ring stiffness; (2) Insufficient wear resistance: During the drainage and sewage discharge process of the pipeline, the water flow carries sediment particles to scour the pipeline, resulting in pipeline wear. The polyethylene double-wall corrugated pipe itself has poor friction resistance, and the addition of recycled materials further weakens the wear resistance of the pipeline, shortening the service life of the pipe; (3) Compatibility problem: Processing aids (such as mold release agents, plasticizers, etc.) existing in polyethylene recycled materials result in weak interfacial bonding force between the recycled material and the new material, resulting in easy appearance of stress weak points in the pipe and cracking problems during service. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing polyethylene composite materials mixed with high-density polyethylene recycled materials for preparing double-wall corrugated pipes, that is, the poor mechanical properties and wear resistance, and to provide a polyethylene composite material, which improves the interfacial bonding force between high-density polyethylene new materials and high-density polyethylene recycled materials through the synergistic effect of ultra-high molecular weight polyethylene, a compatibilizer and an inorganic filler, thereby improving the mechanical properties and wear resistance of the polyethylene composite materials mixed with high-density polyethylene recycled materials.

[0005] Another object of the present invention is to provide a method for preparing a polyethylene composite material.

[0006] Another object of the present invention is to provide an application of a polyethylene composite material in the preparation of a double-wall corrugated pipe.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A polyethylene composite material, comprising the following components by weight:

[0009] 100 parts of high-density polyethylene, 6-20 parts of high-density polyethylene recycled material, 3-16 parts of ultra-high molecular weight polyethylene, 1-6 parts of compatibilizer, 1-2 parts of inorganic filler, 1-2 parts of flow modifier; 2-3 parts of masterbatch; the weight ratio of ultra-high molecular weight polyethylene to high-density polyethylene recycled material is greater than or equal to 0.5; the weight of compatibilizer and high-density polyethylene recycled material is (0.2-0.3): 1;

[0010] The viscosity-average relative molecular weight of the ultra-high molecular weight polyethylene is 1.8 to 2 million, and the testing standard is ASTM D4020.

[0011] The inventors of the present invention have discovered that the polyethylene composite material of the present invention, through the synergistic effect of ultra-high molecular weight polyethylene, compatibilizer and inorganic filler, can make up for the deficiencies of some high-density polyethylene recycled materials, improve the interface bonding force between high-density polyethylene new materials and high-density polyethylene recycled materials, and improve the mechanical properties and wear resistance of the polyethylene composite material mixed with high-density polyethylene recycled materials.

[0012] Among them, it should be noted that:

[0013] The molecular chains of ultra-high molecular weight polyethylene are very long and highly entangled, endowing it with excellent usage characteristics such as impact resistance, abrasion resistance, self-lubrication, and low-temperature resistance. In the present invention, ultra-high molecular weight polyethylene with a specific dosage and specific molecular weight can compensate for the deficiencies in the performance of recycled high-density polyethylene materials and improve the mechanical properties of polyethylene composites. As the dosage of recycled high-density polyethylene increases, the dosage of ultra-high molecular weight polyethylene can also be increased accordingly. However, the dosage of ultra-high molecular weight polyethylene cannot be excessive. Due to its extremely high molecular weight, the melt fluidity is very poor, and shear fracture is likely to occur, making its forming and processing difficult. If the viscosity-average relative molecular weight of ultra-high molecular weight polyethylene is too high, it will result in a large processing viscosity of the composite material and difficult processing. If the viscosity-average relative molecular weight of ultra-high molecular weight polyethylene is too small, it cannot play a role in improving the mechanical properties and wear resistance of the composite material.

[0014] Inorganic fillers are dispersed in the polymer matrix, which can increase the material hardness and simultaneously form a dense wear-resistant layer, effectively inhibiting the plastic deformation and loss of the material during the friction process and improving the wear resistance of the material.

[0015] The compatibilizer can improve the interfacial bonding force between recycled high-density polyethylene and inorganic fillers in high-density polyethylene. Therefore, as the dosage of recycled high-density polyethylene increases, the dosage of the corresponding compatibilizer also increases accordingly. However, if the dosage of the compatibilizer is excessive, it will cause a decrease in the mechanical properties of the material.

[0016] The dosage of recycled high-density polyethylene cannot be excessive. Excessive recycled high-density polyethylene will result in too low mechanical properties of the composite material. Too little recycled high-density polyethylene cannot play a role in reducing the cost of the composite material.

[0017] Compared with the existing technologies, the materials of the present invention have the advantages of realizing the recycling of plastic resources and reducing environmental pollution, and at the same time, the performance of the products is also better.

[0018] Preferably, in the present invention, the density of the high-density polyethylene ≥ 0.94 g / cm 3 , and the melt mass flow rate is 0.2 - 0.5 g / 10 min. The test standard for the melt mass flow rate is GB / T3682.1 - 2018, and the test conditions are 5 kg and 190 °C.

[0019] Preferably, the melt mass flow rate of the recycled high-density polyethylene is 2 - 5 g / 10 min, the test standard is GB / T 3682.1 - 2018, and the test conditions are 5 kg and 190 °C.

[0020] The recycled high-density polyethylene is clean recycled material generated during the production of high-density polyethylene products. For example, clean recycled material generated during production debugging. This clean recycled material has undergone processes such as high-temperature shear plasticization, mechanical crushing, and re-granulation, resulting in partial chain breakage and a decrease in molecular weight. Therefore, the melt mass flow rate increases, but the melt mass flow rate is not excessively high.

[0021] Preferably, the weight ratio of the ultra-high molecular weight polyethylene to the recycled high-density polyethylene is (0.5 - 2.5):1.

[0022] More preferably, the weight ratio of the ultra-high molecular weight polyethylene to the recycled high-density polyethylene is (0.6 - 0.7):1.

[0023] Preferably, the inorganic filler is one or more of nano-silica, nano-titanium dioxide, or graphite.

[0024] The D50 particle size of the nano-silica and nano-titanium dioxide is 20 - 50 nm.

[0025] More preferably, the inorganic filler is a mixture of one or more of nano-silica and nano-titanium dioxide and graphite; in the inorganic filler, the weight content of graphite is 20% - 40%. Graphite has the function of reducing the friction coefficient.

[0026] Preferably, the compatibilizer is maleic anhydride grafted polyethylene and / or glycidyl methacrylate grafted polyethylene.

[0027] Maleic anhydride grafted polyethylene and glycidyl methacrylate grafted polyethylene are both products of solution grafting or melt grafting of polyethylene at high temperature. Their polarity increases, and their adhesion or bonding performance to other materials is enhanced. An appropriate addition amount can help improve the interfacial fusion of each component in the pipe and improve the material quality.

[0028] Preferably, in the compatibilizer, the mass grafting rate of maleic anhydride is 0.8 - 1.2%.

[0029] Preferably, in the compatibilizer, the mass grafting rate of glycidyl methacrylate is 6%.

[0030] Preferably, the flow modifier is polyethylene wax.

[0031] Preferably, the masterbatch is composed of high-density polyethylene, carbon black, light stabilizer, and antioxidant.

[0032] The present invention also protects a method for preparing the polyethylene composite material according to any one of the above, comprising the following steps:

[0033] S1. Mix the recycled high-density polyethylene, ultra-high molecular weight polyethylene, compatibilizer, inorganic filler, and flow modifier evenly, and granulate them in a twin-screw machine to obtain mixture A;

[0034] S2. Mix the mixture A obtained in step S1, high-density polyethylene, and masterbatch evenly, and melt and plasticize them through a single-screw extruder to obtain a polyethylene composite material.

[0035] The present invention also protects the application of the polyethylene composite material described in any one of the above in the preparation of polyethylene double-wall corrugated pipes.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] The present invention discloses a polyethylene composite material. Through the synergistic effect of ultra-high molecular weight polyethylene with a specific molecular weight, compatibilizer, and inorganic filler, the interfacial bonding force between the virgin high-density polyethylene and the recycled high-density polyethylene is improved, and the mechanical properties and wear resistance of the polyethylene composite material containing the recycled high-density polyethylene are enhanced. Specific Embodiments

[0038] The following further illustrates the present invention in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents.

[0039] High-density polyethylene 1, manufacturer: Sinopec, grade: PN049; density is 0.949 g / cm 3 , and the melt mass flow rate is 0.3 g / 10 min;

[0040] High-density polyethylene 2, manufacturer: Fushun Petrochemical, grade: HDPE 100N; density is 0.948 g / cm 3 , and the melt mass flow rate is 0.22 g / 10 min;

[0041] Recycled high-density polyethylene 1, clean recycled material generated during the production of high-density polyethylene products, melt mass flow rate is 2 g / 10 min;

[0042] Recycled high-density polyethylene 2, clean recycled material generated during the production of high-density polyethylene products, melt mass flow rate is 5 g / 10 min;

[0043] Ultra-high molecular weight polyethylene 1, manufacturer: Mitsui Chemicals, Inc., grade: 240S, viscosity-average molecular weight is 2 million;

[0044] Ultra-high molecular weight polyethylene 2, manufacturer: Mitsui Chemicals, Inc., grade: PM-200, viscosity-average molecular weight is 1.8 million;

[0045] Ultra-high molecular weight polyethylene 3, manufacturer: Mitsui Chemicals, Inc., grade: 145M, viscosity-average molecular weight is 1.1 million;

[0046] Ultra-high molecular weight polyethylene 4, manufacturer: Mitsui Chemicals, Inc., grade: P320MU, viscosity-average molecular weight is 3.3 million;

[0047] Compatibilizer 1, maleic anhydride grafted polyethylene; manufacturer: ExxonMobil, grade: Exxelor PE 1040, mass grafting rate of maleic anhydride is 0.8 - 1.2%;

[0048] Compatibilizer 2, glycidyl methacrylate grafted polyethylene; manufacturer: Sumitomo Chemical, grade: BF-2C, mass grafting rate of glycidyl methacrylate is 6%;

[0049] Inorganic filler 1, nano-silica, D50 diameter is 50nm;

[0050] Inorganic filler 2, nano-titanium dioxide, D50 diameter is 20nm;

[0051] Inorganic filler 3, graphite;

[0052] Flow modifier, polyethylene wax, commercially available and the same one is used in parallel examples and comparative examples;

[0053] Masterbatch, manufacturer: Gaoming Caiyingfu, model: 2826-5.

[0054] Examples 1 - 15

[0055] A polyethylene composite material, by weight, comprises the following components:

[0056] High-density polyethylene, high-density polyethylene recycled material, ultra-high molecular weight polyethylene, compatibilizer, inorganic filler, flow modifier; masterbatch.

[0057] The specific content of each component is shown in Table 1 below.

[0058] Table 1: Composition of polyethylene composite materials in each example (by weight)

[0059]

[0060]

[0061] Continued Table 1

[0062]

[0063] The preparation method of the above polyethylene composite material is as follows:

[0064] S1. Mix the recycled high-density polyethylene, ultra-high molecular weight polyethylene, compatibilizer, inorganic filler, and flow modifier evenly and dry them by passing hot air. Granulate them in a twin-screw machine to obtain mixture A.

[0065] S2. Mix the mixture A obtained in step S1, high-density polyethylene, and color masterbatch evenly and dry them by passing hot air. Melt and plasticize them through a single-screw extruder to obtain a polyethylene composite material.

[0066] Comparative Examples 1 - 10

[0067] A polyethylene composite material, by weight, comprises the following components:

[0068] High-density polyethylene, recycled high-density polyethylene, ultra-high molecular weight polyethylene, compatibilizer, inorganic filler, flow modifier; color masterbatch.

[0069] The specific content of each component is shown in Table 2 below.

[0070] Table 2: Composition of the polyethylene composite materials in each comparative example (by weight)

[0071]

[0072] The preparation method of the above polyethylene composite material is the same as that of Example 1 and will not be elaborated here.

[0073] Result Detection

[0074] Conduct relevant performance tests on the polyethylene composite materials of the above examples and comparative examples:

[0075] (1) Wear amount: The test standard is GB / T 3960-2016. The smaller the wear amount, the better the wear resistance. The unit is mg.

[0076] (2) Coefficient of friction: The test standard is GB / T 3960—2016.

[0077] Melt and plasticize a part of the polyethylene composite materials of the above examples and comparative examples through a single-screw extruder and directly extrude the inner wall matrix of the double-wall corrugated pipe. The temperature of the extruder is 160 - 210°C. Extrude the outer wall polyethylene corrugated pipe layer of the double-wall corrugated pipe through another single-screw extruder directly. The temperature of the extruder is 180 - 220°C. Prepare a double-wall corrugated pipe with DN / ID300 and SN12.5, and conduct relevant performance tests on the prepared double-wall corrugated pipe:

[0078] (3) Ring stiffness: The test standard is GB / T9647-2015. The greater the ring stiffness, the better the performance.

[0079] The specific test results of each embodiment and comparative example are described in Table 3 below:

[0080] Table 3

[0081]

[0082] It can be seen from the above results that the polyethylene composite material of the present invention can make up for the deficiency of part of the high-density polyethylene recycled material through the synergistic effect of ultra-high molecular weight polyethylene, compatibilizer and inorganic filler, improve the interface bonding force between high-density polyethylene new material and high-density polyethylene recycled material, and improve the mechanical properties and wear resistance of the polyethylene composite material mixed with high-density polyethylene recycled material. The polyethylene composite material of the present invention has a wear loss of less than 11mg, a friction coefficient of less than 0.25, and a ring stiffness of the prepared double-wall corrugated pipe of more than 12.5kN / m 2 .

[0083] It can be seen from the examples and comparative example 1 that the weight ratio of the ultra-high molecular weight polyethylene to the high-density polyethylene recycled material is less than 0.5, and the ring stiffness of the pipe is too low.

[0084] It can be seen from the embodiment, comparative example 2 and comparative example 3 that the weight of the compatibilizer and the high-density polyethylene recycled material is too large or too small, and the ring stiffness of the pipe is too low.

[0085] It can be seen from the embodiment and comparative example 4 that there is too much high-density polyethylene recycled material and the ring stiffness of the pipe is too low.

[0086] It can be seen from the examples and comparative example 5 that without adding inorganic fillers, the ring stiffness of the pipe is too low.

[0087] It can be seen from the embodiment and comparative examples 6 and 7 that the viscosity average relative molecular weight of the ultra-high molecular weight polyethylene is too small and the ring stiffness of the pipe is too low. The viscosity average relative molecular weight of the ultra-high molecular weight polyethylene is too large and the viscosity of the ultra-high molecular weight polyethylene is high, making it difficult to form.

[0088] It can be seen from the examples and comparative example 8 that without adding ultra-high molecular weight polyethylene, the ring stiffness of the pipe is too low.

[0089] It can be seen from the examples and comparative example 9 that without adding high-density polyethylene recycled material, inorganic filler, ultra-high molecular weight polyethylene, or compatibilizer, the wear resistance of the pipe is too poor.

[0090] It can be seen from the examples and comparative example 10 that excessive addition of ultra-high molecular weight polyethylene makes molding and processing difficult.

[0091] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A polyethylene composite material, characterized in that, By weight parts, it includes the following components: 100 parts of high-density polyethylene, 6 - 20 parts of high-density polyethylene recycled material, 3 - 16 parts of ultra-high molecular weight polyethylene, 1 - 6 parts of compatibilizer, 1 - 2 parts of inorganic filler, 1 - 2 parts of flow modifier; 2 - 3 parts of masterbatch; the weight ratio of ultra-high molecular weight polyethylene to high-density polyethylene recycled material is greater than or equal to 0.5; the weight ratio of compatibilizer to high-density polyethylene recycled material is (0.2 - 0.3):1; Among them, the viscosity-average relative molecular weight of the ultra-high molecular weight polyethylene is 1.8 million - 2 million, and the test standard is ASTM D4020.

2. The polyethylene composite material according to claim 1, wherein, The melt mass-flow rate of the high-density polyethylene recycled material is 2 - 5 g / 10 min, the test standard is GB / T 3682.1 - 2018, and the test conditions are 5 kg, 190 °C.

3. The polyethylene composite material according to claim 1, wherein The weight ratio of the ultra-high molecular weight polyethylene to the high-density polyethylene recycled material is (0.6 - 0.7):

1.

4. The polyethylene composite material according to claim 1, wherein The inorganic filler is one or more of nano-silica, nano-titanium dioxide or graphite.

5. The polyethylene composite material according to claim 4, characterized in that, The inorganic filler is a mixture of one or more of nano-silica and nano-titanium dioxide and graphite; in the inorganic filler, the weight content of graphite is 20% - 40%.

6. The polyethylene composite material according to claim 1, wherein The compatibilizer is maleic anhydride grafted polyethylene and / or glycidyl methacrylate grafted polyethylene.

7. The polyethylene composite material according to claim 1, characterized in that, The flow modifier is polyethylene wax.

8. The polyethylene composite material according to claim 1, wherein The masterbatch is composed of high-density polyethylene, carbon black, light stabilizer and antioxidant.

9. The preparation method of the polyethylene composite material according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Mix the high-density polyethylene recycled material, ultra-high molecular weight polyethylene, compatibilizer, inorganic filler, and flow modifier evenly, and granulate in a twin-screw machine to prepare a mixture A; S2. Mix the mixture A obtained in step S1, high-density polyethylene and masterbatch evenly, and melt and plasticize through a single-screw extruder to obtain a polyethylene composite material.

10. The application of the polyethylene composite material according to any one of claims 1 - 8 in the preparation of polyethylene double-wall corrugated pipes.

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