Wear-resistant polyethylene composite material and preparation method and application thereof

Abstract

The application discloses a wear-resistant polyethylene composite material and a preparation method and application thereof. The wear-resistant polyethylene composite material comprises the following components in parts by weight: 40-75 parts of high-density polyethylene, 8-15 parts of natural rubber, 25-40 parts of glass fiber, 2-6 parts of a compatilizer, 0.1-1 part of an antioxidant, 0-1 part of a processing aid, and 0.9-4.2 parts of a crosslinking agent; the crosslinking agent is an organic peroxide, and the average particle size of the natural rubber is less than or equal to 2 mm. The wear-resistant polyethylene composite material is formed by the natural rubber with a specific particle size, high-density polyethylene, glass fiber and a compatilizer under the action of a crosslinking agent, so that the wear-resistant performance is greatly improved; meanwhile, the crosslinking structure formed by the natural rubber particles and the crosslinking agent improves the elongation at break and the impact resistance of the polyethylene composite material, so that the risk of cracking caused by external impact is reduced, and the usability and service life of the material are improved.

Description

Technical Field

[0001] This invention relates to the field of polymer composition technology, and more specifically, to a wear-resistant polyethylene composite material, its preparation method, and its application. Background Technology

[0002] Polyethylene is one of the most widely used materials in the plastics industry, applied not only to packaging, pipes, and furniture, but also increasingly in coal mining. For example, glass fiber reinforced polyethylene composites are being used to replace metal guide rails in coal mining, effectively preventing sparks from collisions between ore and metal rails during coal transportation and improving production safety. However, while glass fiber reinforced polyethylene composites possess good strength, their wear resistance is poor. During long-term rotation and friction with the coal basket, the guide rails are prone to wear and deformation, even premature wear through, leading to a reduced product lifespan.

[0003] Currently, the wear resistance of glass fiber reinforced polyethylene composites is generally improved by adding resins or inorganic fillers with excellent wear resistance properties. For example, an existing technology discloses a wear-resistant polyethylene composite material, which is made from 100 parts high-density polyethylene, 6-12 parts coupling agent-modified molybdenum disulfide, 1-5 parts nano-ceramic powder, 1-5 parts ultrafine carbon black, 2-7 parts polytetrafluoroethylene, and 0.5-1.0 parts calcium stearate. Different inorganic fillers are combined to form wear-resistant modifiers to improve the wear resistance of polyethylene composites. However, a large amount of wear-resistant modifier is usually required, which in turn leads to poor mechanical properties of the polyethylene composite material.

[0004] To mitigate the impact of inorganic wear-resistant additives, a wear-resistant crosslinkable polyethylene composition is disclosed in the prior art. This composition comprises the following components: high-density polyethylene (HDPE), low-density polyethylene (LDPE), crosslinking masterbatch, antioxidant, and additives. The additives are inorganic fillers and / or organic modifiers. The inorganic fillers are selected from at least one of glass flakes, glass fibers, copper oxide, graphene, carbon nanotubes, molybdenum disulfide, and quartz powder. The organic modifiers are selected from at least one of polyoxymethylene (POM), thermoplastic phenolic resin, thermoplastic urea-formaldehyde resin, thermoplastic melamine-formaldehyde resin, polyurethane, polytetrafluoroethylene (PTFE), and nylon. By adding crosslinking masterbatch, antioxidant, inorganic fillers, and / or organic modifiers, and limiting the types of inorganic fillers and / or organic modifiers, a crosslinkable polyethylene system with high melt strength and wear resistance is formed. This allows the wear-resistant crosslinked polyethylene material prepared from this composition to possess both good wear resistance and mechanical properties, but its long-term durability needs further improvement.

[0005] For example, the prior art also discloses a high-impact and wear-resistant glass fiber reinforced POK-HDPE composite material and its preparation method. By selecting polyketide resin and high-density polyethylene as the matrix resin, and combining them with a wear-resistant agent coated with a polyethylene glycol film on the surface, the bonding force between the wear-resistant agent and the matrix resin is improved. At the same time, peroxide and maleic anhydride are added to enhance the interfacial bonding force between the components, which improves the wear resistance of the polyethylene composite material to a certain extent. However, due to the poor compatibility between POK and HDPE and the large difference in shrinkage, its long-term wear resistance is poor. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and deficiencies of existing polyethylene composite materials in terms of poor long-term wear resistance, and to provide a wear-resistant polyethylene composite material. This material utilizes natural rubber of a specific particle size, high-density polyethylene, glass fiber, and a compatibilizer, under the action of a crosslinking agent, to reduce the porosity between the components and the glass fiber, forming a tightly bonded composite material that significantly improves wear resistance. Simultaneously, the crosslinked structure formed by the natural rubber particles and the crosslinking agent improves the elongation at break and impact resistance of the polyethylene composite material, reducing the risk of cracking under external impact and enhancing the material's usability and service life.

[0007] Another object of the present invention is to provide a method for preparing abrasion-resistant polyethylene composite material.

[0008] Another object of the present invention is to provide an application of the above-mentioned wear-resistant polyethylene composite material in coal mining tools.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] This invention protects a wear-resistant polyethylene composite material, comprising the following components by weight:

[0011] The composition comprises 40-75 parts high-density polyethylene (HDPE), 8-15 parts natural rubber (NR), 25-40 parts glass fiber, 2-6 parts compatibilizer, 0.1-1 part antioxidant, 0-1 part processing aid, and 0.9-4.2 parts crosslinking agent; wherein the crosslinking agent is an organic peroxide, and the average particle size of the natural rubber is ≤2mm.

[0012] The wear-resistant polyethylene composite material of the present invention utilizes natural rubber of a specific particle size, high-density polyethylene, glass fiber, and compatibilizer, under the action of a crosslinking agent, to reduce the porosity between each component and the glass fiber, forming a tightly bonded composite material, thereby significantly improving wear resistance. At the same time, the crosslinked structure formed by natural rubber particles and the crosslinking agent improves the elongation at break and impact resistance of the polyethylene composite material, thereby reducing the risk of cracking due to external impact and improving the usability and service life of the material.

[0013] Preferably, the wear-resistant polyethylene composite material comprises, by weight, the following components:

[0014] 50-64 parts high-density polyethylene, 10-13 parts natural rubber, 30-35 parts glass fiber, 3-5 parts compatibilizer, 0.2-0.6 parts antioxidant, 0.2-0.6 parts processing aid, and 1-4.1 parts crosslinking agent.

[0015] Optionally, the high-density polyethylene, according to GB / T3682.1:2018 standard, has a melt mass flow rate of ≤10g / 10min at 190℃ and 2.16kg, preferably 0.3~8g / 10min, specifically 0.5g / 10min, 1g / 10min, 1.5g / 10min, 2g / 10min, 2.5g / 10min, 3g / 10min, 5g / 10min or 7g / 10min.

[0016] Optionally, the average particle size of the natural rubber is ≤1.0 mm, preferably 0.5 mm to 2.0 mm.

[0017] Specifically, the organic peroxide is dicumyl peroxide and / or di-tert-butyl peroxide; preferably, the organic peroxide is dicumyl peroxide, which is a solid powder, and is more uniform and safer in the subsequent mixing process.

[0018] Specifically, the compatibilizer is maleic anhydride-grafted polyolefin, such as maleic anhydride-grafted ABS, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, maleic anhydride-grafted PS, maleic anhydride-grafted POE, and maleic anhydride-grafted EVA. Preferably, the compatibilizer is maleic anhydride-grafted polyethylene.

[0019] Specifically, the antioxidant is one or more of hindered phenolic antioxidants or phosphate ester antioxidants, such as antioxidant CA, antioxidant 330, antioxidant 1076, antioxidant 1010, antioxidant 168, antioxidant 1790 or antioxidant 412S; the processing aid is a lubricant, which mainly includes internal lubricants (reducing friction between molecular chains) and external lubricants (reducing adhesion between polymer melt and metal surface), such as erucamide, oleamide, EBS amides, PE wax and stearates, one or more of these.

[0020] This invention also protects a method for preparing a wear-resistant polyethylene composite material, comprising the following steps:

[0021] S1. High-density polyethylene, natural rubber, glass fiber, compatibilizer, antioxidant and processing aid are mixed and melt-extruded at 150℃~180℃ to obtain HDPE / NR / glass fiber composite.

[0022] S2. Mix the HDPE / NR / glass fiber composite in S1 with a crosslinking agent and melt-extrude to obtain the wear-resistant polyethylene composite material.

[0023] Specifically, a twin-screw extruder can be used for melt extrusion. High-density polyethylene, natural rubber, compatibilizer, antioxidant, and processing aids are added to the twin-screw extruder through the main feed port, while glass fiber is added through the side feed port. The melt extrusion temperature is controlled to be stable between 150°C and 180°C to prevent the decomposition of natural rubber.

[0024] The application of the aforementioned wear-resistant polyethylene composite material in coal mining tools is also within the scope of protection of this invention. Specifically, coal mining tools can be components such as guide rails, shafts, and load-bearing baskets that are subject to friction or frequent impacts.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The wear-resistant polyethylene composite material of the present invention utilizes natural rubber of a specific particle size, high-density polyethylene, glass fiber, and compatibilizer, under the action of a crosslinking agent, to reduce the porosity between each component and the glass fiber, forming a tightly bonded composite material, thereby significantly improving wear resistance. At the same time, the crosslinked structure formed by natural rubber particles and the crosslinking agent improves the elongation at break and impact resistance of the polyethylene composite material, thereby reducing the risk of cracking due to external impact and improving the usability and service life of the material. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0028] 1. Raw materials and reagents

[0029] (1) High-density polyethylene

[0030] PE-1, melt index 0.3g / 10min, grade HDPE 5502, manufacturer: Yangzi Petrochemical;

[0031] PE-2, melt index 8g / 10min, grade HDPE 8008, manufacturer is Qilu Petrochemical.

[0032] (2) Natural rubber

[0033] Natural rubber of grade SVR10, manufactured by Shanghai Fuyou, was ground into rubber powder of different particle sizes using a vertical ball mill.

[0034] NR-1 has an average particle size of 2.0 mm; NR-2 has an average particle size of 1.0 mm; NR-3 has an average particle size of 0.5 mm; and NR-4 has an average particle size of 4.0 mm.

[0035] (3) The compatibilizer is maleic anhydride grafted POE, brand name is N406, and manufacturer is Shanghai Rizhisheng;

[0036] (4) Glass fiber, brand name ECS13-03-508A, manufacturer is Zhejiang Jushi;

[0037] (5) The antioxidant is 1010 and the processing aid is EBS, both of which are commercially available;

[0038] (6) Crosslinking agent

[0039] Crosslinking agent 1 is dicumyl peroxide, manufactured by Merck Chemicals;

[0040] Crosslinking agent 2 is di-tert-butyl peroxide, manufactured by Merck Chemicals.

[0041] 2. The wear-resistant polyethylene composite materials of the various embodiments and comparative examples of the present invention were prepared by the following preparation method:

[0042] S1. High-density polyethylene, natural rubber, glass fiber, compatibilizer, antioxidant and processing aid are mixed and melt-extruded at 150℃~180℃ to obtain HDPE / NR / glass fiber composite.

[0043] S2. The HDPE / NR / glass fiber composite in S1 is mixed with a crosslinking agent and then added to a twin-screw extruder. The mixture is then melt-extruded at 150℃~180℃ to obtain the wear-resistant polyethylene composite material.

[0044] 3. Performance Testing

[0045] (1) Tensile strength: The wear-resistant polyethylene composite materials in each example and comparative example were made into dumbbell-shaped specimens and tested according to GB / T1040.1-2006 standard, with a tensile rate of 10 mm / min.

[0046] (2) Elongation at break: The wear-resistant polyethylene composite materials in each example and comparative example were made into dumbbell-shaped specimens and tested according to GB / T1040.1-2006 standard, with a tensile rate of 10 mm / min.

[0047] (3) Impact strength: The wear-resistant polyethylene composite material injection molded notched specimens from each embodiment and comparative example were tested in accordance with GB / T1843-2008 standard.

[0048] (4) Wear: The wear-resistant polyethylene composite materials in each embodiment and comparative example were made into square plates with a length, width and height of 100mm*100mm*3mm, and tested according to GMW 14867-3.11-2010 standard. The load was 500g and the number of cycles was 20,000.

[0049] Examples 1-11 and Comparative Examples 1-4

[0050] The weight proportions of each component in the wear-resistant polyethylene composite materials of Examples 1-11 and Comparative Examples 1-4 are shown in Table 1.

[0051] Table 1 shows the weight parts of each component in the wear-resistant polyethylene composite materials of Examples 1-11 and Comparative Examples 1-4.

[0052]

[0053] The performance test results of the wear-resistant polyethylene composite materials in each embodiment and comparative example according to the methods mentioned above are shown in Table 2.

[0054] Table 2 Test results for each embodiment and comparative example

[0055]

[0056]

[0057] According to the data in Table 3, the wear-resistant polyethylene composite materials in Examples 1-11 not only possess good rigidity and toughness properties, with tensile strength exceeding 60 MPa and elongation at break exceeding 15%, but also have a notched impact strength of 24 kJ / m. 2 In addition, it also has excellent long-term wear resistance. The wear amount after 20,000 cycles under a 500g load is less than or equal to 3.6g, indicating that the wear-resistant polyethylene composite material of the present invention has both good rigidity and toughness properties and excellent long-term wear resistance.

[0058] As can be seen from Examples 1, 3-4, and Comparative Example 1, a cross-linked network can only be effectively formed to improve the rigidity, toughness, and wear resistance of polyethylene composites when the average particle size of natural rubber is less than or equal to 2.0 mm. Furthermore, the effect is even better when the average particle size of natural rubber is in the range of 0.5-1.0 mm. Comparative Examples 2 and 3 show that both excessively high and low natural rubber content in the wear-resistant polyethylene composites are detrimental to improving the rigidity, toughness, and wear resistance of the polyethylene composites. A low cross-linking agent content leads to insufficient cross-linking, resulting in a sharp decrease in the rigidity, toughness, and wear resistance of the polyethylene composites. Conversely, an excessive cross-linking agent content leads to over-cross-linking, weakening the elasticity of the polyethylene composites and hindering the improvement of wear resistance.

[0059] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. 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 describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A wear-resistant polyethylene composite material, characterized in that, By weight, it includes the following components: The composition comprises 40-75 parts high-density polyethylene, 8-15 parts natural rubber, 25-40 parts glass fiber, 2-6 parts compatibilizer, 0.1-1 part antioxidant, 0-1 part processing aid, and 0.9-4.2 parts crosslinking agent; wherein the crosslinking agent is an organic peroxide, and the average particle size of the natural rubber is ≤2mm.

2. The wear-resistant polyethylene composite material according to claim 1, characterized in that, By weight, it includes the following components: 50-64 parts high-density polyethylene, 10-13 parts natural rubber, 30-35 parts glass fiber, 3-5 parts compatibilizer, 0.2-0.6 parts antioxidant, 0.2-0.6 parts processing aid, and 1-4.1 parts crosslinking agent.

3. The wear-resistant polyethylene composite material according to claim 1, characterized in that, The average particle size of the natural rubber is 0.5 to 1.0 mm.

4. The wear-resistant polyethylene composite material according to any one of claims 1 to 3, characterized in that, The organic peroxide is dicumyl peroxide and / or di-tert-butyl peroxide.

5. The wear-resistant polyethylene composite material according to any one of claims 1 to 3, characterized in that, The compatibilizer is maleic anhydride-grafted polyolefin.

6. The wear-resistant polyethylene composite material according to claim 5, characterized in that, The compatibilizer is maleic anhydride-grafted polyethylene.

7. The wear-resistant polyethylene composite material according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 1790 and antioxidant 412S.

8. The wear-resistant polyethylene composite material according to claim 1, characterized in that, The processing aid is a lubricant, and is selected from one or more of erucamide, oleamide, EBS amides, PE wax and stearates.

9. A method for preparing the wear-resistant polyethylene composite material according to any one of claims 1 to 8, comprising the following steps: S1. High-density polyethylene, natural rubber, glass fiber, compatibilizer, antioxidant and processing aid are mixed and melt-extruded at 150-180°C to obtain HDPE / NR / glass fiber composite. S2. Mix the HDPE / NR / glass fiber composite in S1 with a crosslinking agent and melt-extrude to obtain the wear-resistant polyethylene composite material.

10. The application of the wear-resistant polyethylene composite material according to any one of claims 1 to 8 in coal mine tools.

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