Temperature resistance and wear resistance enhancing process, ultra-high molecular weight polyethylene plate and preparation method of ultra-high molecular weight polyethylene plate

Abstract

The invention provides a temperature resistance and wear resistance enhancing process, an ultra-high molecular weight polyethylene plate and a preparation method of the ultra-high molecular weight polyethylene plate, and relates to the technical field of temperature resistance and wear resistance materials. The enhancement process comprises the following steps: adding chlorinated polyethylene and / or superfine polyethylene powder into ultra-high molecular weight polyethylene, and carrying out temperature-controlled blending with an additive to form ultra-high molecular weight polyethylene with a net structure after blending. The enhancement process is used for modifying the ultra-high molecular weight polyethylene, so that the chain structure of the ultra-high molecular weight polyethylene molecule is changed into a net structure, the physical and chemical properties of the ultra-high molecular weight polyethylene molecule can be improved through the formation of the net structure, and meanwhile, the ultra-high molecular weight polyethylene is mixed with different components to realize modification of different properties; the modified ultra-high molecular weight polyethylene is used as a raw material to prepare the ultra-high molecular weight polyethylene plate through the preparation method, and the temperature resistance and wear resistance of the ultra-high molecular weight polyethylene plate can be greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of heat-resistant and wear-resistant materials, and in particular to a process for enhancing the heat-resistant and wear-resistant performance of an ultra-high molecular weight polyethylene plate, an ultra-high molecular weight polyethylene plate and a preparation method thereof. Background Art

[0002] With the sustained development of the national economy and the accelerated advancement of industrialization, the heat-resistant and wear-resistant materials industry has grown rapidly. As an important basic material in industrial production, the market demand for heat-resistant and wear-resistant materials has shown a steady growth trend, and the scale of the industry is also expanding, which is mainly due to the support of national policies. In the future, with the further advancement of industrialization and the continuous innovation of technology, the demand for heat-resistant and wear-resistant materials (inorganic materials and organic materials) in the market will continue to grow.

[0003] The existing organic material wear-resistant plates mainly include: nylon, polyurethane, tetrafluoroethylene plate and ultra-high molecular weight polyethylene plate. The disadvantage of nylon material is that its wear resistance is unstable. Due to the decrease in temperature, its wear resistance becomes fragile and easily breaks; the weakness of polyurethane is that the friction between soft and soft is relatively stable, but the friction between soft and hard cannot last long, and it is easy to break at the contact position; tetrafluoroethylene plate is generally not popularized and applied due to its high price; ultra-high molecular weight polyethylene plate has excellent performance, corrosion resistance, high pressure resistance, impact resistance and wear resistance, but the disadvantage is that it is not resistant to high temperature.

[0004] Therefore, there are areas for improvement. How to improve the high temperature resistance and wear resistance of ultra-high molecular polyethylene sheets is an urgent problem to be solved in the organic materials industry and the field of organic wear-resistant materials.

[0005] To this end, the present invention provides a process for enhancing the heat resistance and wear resistance of an ultra-high molecular weight polyethylene plate, as well as an ultra-high molecular weight polyethylene plate and a preparation method thereof. Summary of the invention

[0006] In view of the shortcomings of the prior art, one of the purposes of the present invention is to propose a process for enhancing the heat resistance and wear resistance of ultra-high molecular weight polyethylene plates. The specific scheme is as follows: A process for enhancing the heat and wear resistance of an ultra-high molecular weight polyethylene plate. The raw material of the ultra-high molecular weight polyethylene plate is ultra-high molecular weight polyethylene. The enhancing process comprises adding chlorinated polyethylene and / or ultra-fine polyethylene powder to the ultra-high molecular weight polyethylene, and blending the mixture with the additives under controlled temperature to form an ultra-high molecular weight polyethylene with a network structure.

[0007] Furthermore, the ultrafine polyethylene powder is subjected to nitriding treatment.

[0008] Furthermore, the nitridation treatment is specifically as follows: ultra-high molecular weight polyethylene is placed in a reactor and stirred, liquid ammonia is added, a DC power supply with a voltage of 600 V is introduced, and at the same time, the pressure in the reactor is increased to 5 MPa, and the temperature is controlled at 30°C, and then pure nitrogen is introduced at a flow rate of 5 L / min. The nitrogen ions formed in the liquid nitrogen are continuously combined with the ultra-high molecular weight polyethylene, and after cooling, fine particles of a preset particle size are screened out to obtain ultrafine polyethylene powder.

[0009] Furthermore, the particle size of the ultrafine polyethylene powder is 100-130 meshes.

[0010] Furthermore, the chlorinated polyethylene is prepared from high-density polyethylene through a chlorination substitution reaction.

[0011] Furthermore, the enhancement process includes the following three modes: Mode S1: Add chlorinated polyethylene to ultra-high molecular weight polyethylene, put it into a reaction pot equipped with a stirrer and a thermometer, add stearic acid and calcium oxide, heat and blend until the temperature reaches 140-150°C, the reaction time is 1.5-2.0h, and after blending, obtain modified ultra-high molecular weight polyethylene A; Mode S2: Adding ultrafine polyethylene powder that has been nitrided to ultra-high molecular weight polyethylene, adding microcrystalline wax and putting them into a high-speed mixer for fusion, heating the fusion temperature to 150°C, melting and mixing at high temperature, cooling and solidifying to obtain modified ultra-high molecular weight polyethylene B; Mode S3: Add modified ultra-high molecular weight polyethylene A and modified ultra-high molecular weight polyethylene B into ultra-high molecular weight polyethylene, and then put them into a high-speed mixer for fusion. The fusion temperature is heated to 130°C. After the mixture is evenly mixed, cooled and solidified, modified ultra-high molecular weight polyethylene C can be obtained.

[0012] The second object of the present invention is to provide an ultra-high molecular weight polyethylene sheet, the specific scheme is as follows: An ultra-high molecular weight polyethylene plate, the ultra-high molecular weight polyethylene plate is a multi-layer structure, and the layer structure is made of one or more of modified ultra-high molecular weight polyethylene A, modified ultra-high molecular weight polyethylene B or modified ultra-high molecular weight polyethylene C obtained by a process for enhancing the heat resistance and wear resistance of the ultra-high molecular weight polyethylene plate.

[0013] Furthermore, the layer structure of the ultra-high molecular weight polyethylene plate comprises at least three layers.

[0014] Furthermore, when one layer of the ultra-high molecular weight polyethylene plate is made of modified ultra-high molecular weight polyethylene C, its thickness accounts for at least 2 / 5 of the thickness of the entire ultra-high molecular weight polyethylene plate.

[0015] The third object of the present invention is to provide a method for preparing an ultra-high molecular weight polyethylene sheet, the specific scheme is as follows: A method for preparing an ultra-high molecular weight polyethylene plate comprises the following steps: each layer structure is flattened and evenly spread on the bottom of a mold frame according to a set thickness, then the mold is closed and pressurized, the temperature is raised to 235°C, and the temperature is kept constant for 2 hours, followed by cooling and pressurization, with the pressure being ≥50Mpa per square centimeter, and the mold is removed when the temperature drops to ≤50°C. When the mold is removed, the mold frame is lifted, the plate body is taken out, and the edge skin is removed from the upper and lower sides, and then the plate body is placed in a cold press for shaping to obtain an ultra-high molecular weight polyethylene plate.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The reinforcement process of the present invention is used to modify the raw material (ultra-high molecular weight polyethylene) of the ultra-high molecular weight polyethylene sheet, so that the chain structure of the ultra-high molecular weight polyethylene molecules is transformed into a network structure. The formation of the network structure can improve its physical and chemical properties. At the same time, by mixing the ultra-high molecular weight polyethylene with different components, the modification of different properties can be achieved.

[0017] Specifically, the network structure formed by the cross-linking of ultra-high molecular weight polyethylene and chlorinated polyethylene can enhance its heat resistance, the network structure formed by the cross-linking of ultra-high molecular weight polyethylene and ultrafine polyethylene powder can enhance its heat resistance and wear resistance, and the network structure formed by the dynamic cross-linking of ultra-high molecular weight polyethylene blended with chlorinated polyethylene and ultrafine polyethylene powder at the same time can further enhance its heat resistance, wear resistance, and even flame retardancy. Therefore, the modified ultra-high molecular weight polyethylene obtained by the present invention can meet the requirements of high strength and high rigidity of polymer materials, thereby improving the heat resistance and wear resistance of ultra-high molecular weight polyethylene plates, providing new options for material selection in the heat-resistant and wear-resistant materials industry, and has important application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the chain structure in the ultra-high molecular weight polyethylene of the present invention forming a network structure; Figure 2 It is a schematic diagram of the structure of the ultra-high molecular weight polyethylene plate in the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0020] In the prior art, the raw material of ultra-high molecular weight polyethylene sheet is ultra-high molecular weight polyethylene. Due to its excellent performance, ultra-high molecular weight polyethylene sheet has corrosion resistance, high pressure resistance, impact resistance and wear resistance. The disadvantage is that it is not resistant to high temperature, and the wear resistance performance needs to be improved. The reason is that the molecular structure of the existing ultra-high molecular weight polyethylene is a chain structure, and the chain structures are independent of each other. The material of the ultra-high molecular weight polyethylene with a chain structure has moderate high strength and high rigidity, and melts when heated, becomes solid after cooling, and can melt again after heating, so it has thermoplasticity.

[0021] In this regard, the present invention proposes a process for enhancing the heat resistance and wear resistance of ultra-high molecular weight polyethylene sheets, which involves converting the chain structure of ultra-high molecular weight polyethylene molecules into a mesh structure. Figure 1 The chain structure is transformed into a mesh structure to meet the requirements of high strength and high rigidity of polymer materials, improve the flexibility and adaptability of polymer materials, and enhance the physical and chemical properties of materials. Moreover, the ultra-high molecular weight polyethylene with a mesh structure will not melt when processed and molded, so it has thermosetting properties.

[0022] Specifically, the enhancement process is to add chlorinated polyethylene and / or ultrafine polyethylene powder to ultra-high molecular weight polyethylene, and temperature-controlled blending with additives to modify the chain structure of ultra-high molecular weight polyethylene, and form ultra-high molecular weight polyethylene with a network structure after blending, which meets the requirements of high strength and high rigidity of polymer materials and improves the flexibility and adaptability of the modified ultra-high molecular weight polyethylene. The first is to enhance the physical and chemical properties and improve the wear resistance of ultra-high molecular weight polyethylene sheets, and the second is to enhance the temperature resistance and wear resistance quality, so as to improve the temperature resistance and wear resistance of ultra-high molecular weight polyethylene sheets.

[0023] It should be noted that the ultra-high molecular weight polyethylene can adopt the existing raw materials of Shanghai Lianle, with a molecular weight of 5 million units and a particle size of 120 meshes.

[0024] It should be noted that the ultrafine polyethylene powder has been nitrided. The nitriding treatment is specifically as follows: ultra-high molecular weight polyethylene is placed in a reactor and stirred at a speed of 180r / min, liquid ammonia is added in a weight ratio of 50:1 to ultra-high molecular weight polyethylene, a DC power supply with a voltage of 600V is introduced, and at the same time, the pressure in the reactor is increased to 5MPa, while the temperature is controlled at 30°C, and then pure nitrogen is introduced, and the nitrogen ions formed are continuously combined with the ultra-high molecular weight polyethylene, and finally the ultrafine polyethylene powder is obtained. The particle size of the ultrafine polyethylene powder is also set to 120 mesh, which is convenient for subsequent blending with ultra-high molecular weight polyethylene.

[0025] In the nitriding treatment, liquid ammonia is used to perform a nitriding on the ultra-high molecular weight polyethylene, and the surface ion nitriding treatment is performed. The specific principle is that liquid ammonia nitriding can form a nitrogen-rich hardened layer on the surface of the material, significantly improving the surface hardness of the material, thereby improving the surface properties of the ultra-high molecular weight polyethylene and improving its wear resistance. The specific principle is that a DC power supply with a voltage of 600V can provide sufficient electric field strength. The polyethylene raw material is used as the cathode and placed in a reactor. Under the action of the electric field, the nitrogen ions in the liquid ammonia will be attracted and move to the cathode, promoting the migration of nitrogen ions to the surface of the ultra-high molecular weight polyethylene. At the same time, the liquid ammonia is in a gas-liquid coexistence state under the pressure and temperature in the reactor. Under this reaction condition, it is more conducive to the formation of nitrogen ions. When the nitrogen ions contact the surface of the ultra-high molecular weight polyethylene, a chemical reaction will occur. These reactions include the combination of nitrogen elements and carbon atoms on the surface of polyethylene to form a nitride layer. This layer of nitride layer has excellent hardness and wear resistance, and can significantly improve the surface properties of ultra-fine polyethylene powder.

[0026] It should be noted that chlorinated polyethylene is made from high-density polyethylene through chlorination substitution reaction, that is, the product of partially replacing the hydrogen atoms on the high-density polyethylene (HDPE) molecular chain with chlorine atoms. The chlorinated polyethylene molecule does not contain double chains, has good weather resistance, flame retardancy, thermal stability, low cost, and excellent performance. High-density polyethylene can use the existing Weifang Shuoyi Chemical Co., Ltd., brand: MF2035.

[0027] In order to specifically improve the heat resistance and wear resistance of ultra-high molecular weight polyethylene sheets, the reinforcement process includes the following three modes, and different reinforcement processes target different performances.

[0028] One of the modes is mode S1. Mode S1: add chlorinated polyethylene to ultra-high molecular weight polyethylene, put it into a reaction pot equipped with a stirrer and a thermometer, add stearic acid and calcium oxide, heat and blend until the temperature reaches 140-150°C, the reaction time is 1.5-2.0h, and after blending, obtain modified ultra-high molecular weight polyethylene A.

[0029] It should be noted that on the basis of the high heat resistance of chlorinated polyethylene, ultra-high molecular weight polyethylene and chlorinated polyethylene are blended, and stearic acid enables high molecular weight polyethylene and chlorinated polyethylene to release surface crystals that are convenient for mold opening under high temperature and high pressure. Calcium oxide plays a filling role, reducing the release of internal stress of the plate, thereby greatly improving the heat resistance of this modified ultra-high molecular weight polyethylene A.

[0030] One of the modes is mode S2. Mode S2: Add ultrafine polyethylene powder that has been nitrided to ultra-high molecular weight polyethylene, add microcrystalline wax and put them into a high-speed mixer for fusion. The fusion temperature is heated to 150°C, melt-mixed at high temperature, and cooled and solidified to obtain modified ultra-high molecular weight polyethylene B.

[0031] It should be noted that the blending of ultra-high molecular weight polyethylene with nitrided ultrafine polyethylene powder can increase the hardness of the material and make it more wear-resistant, and microcrystalline wax facilitates demolding. The temperature resistance and wear resistance of the modified ultra-high molecular weight polyethylene B obtained are greatly improved.

[0032] The third mode is mode S3. Mode S3: add modified ultra-high molecular weight polyethylene A and modified ultra-high molecular weight polyethylene B into ultra-high molecular weight polyethylene, and then put them into a high-speed mixer for fusion. The fusion temperature is heated to 130°C. After the mixture is evenly mixed, cooled and solidified, modified ultra-high molecular weight polyethylene C can be obtained.

[0033] It should be noted that the modified ultra-high molecular weight polyethylene C is formed by dynamically cross-linking the modified ultra-high molecular weight polyethylene and the conventional ultra-high molecular weight polyethylene. The temperature resistance and wear resistance of the modified ultra-high molecular weight polyethylene C are not only greatly improved, but also its compression resistance is greatly improved.

[0034] According to the actual demand of ultra-high molecular weight polyethylene sheet, the corresponding reinforcement process can be selected to obtain the corresponding modified ultra-high molecular weight polyethylene, that is, the raw material of ultra-high molecular weight polyethylene sheet.

[0035] In this regard, the present invention further proposes an ultra-high molecular weight polyethylene plate, which has a multi-layer structure, and its layer structure is made of one or more of modified ultra-high molecular weight polyethylene A, modified ultra-high molecular weight polyethylene B or modified ultra-high molecular weight polyethylene C.

[0036] It should be noted that the layer structure of the ultra-high molecular weight polyethylene sheet is provided with at least three layers. The upper layer is the contact layer, which is the thickest as the application layer and is both heat-resistant and wear-resistant; the middle layer is the buffer layer and also the wear-resistant layer, which takes over after the upper layer is worn out; the bottom layer is the connection layer and also the heat-resistant layer, which is connected to the bottom steel plate to prevent the plate body from warping due to the increase of steel plate temperature.

[0037] Wherein, when the layer structure of one layer of the ultra-high molecular weight polyethylene plate is made of modified ultra-high molecular weight polyethylene C, its thickness accounts for at least 2 / 5 of the thickness of the entire ultra-high molecular weight polyethylene plate.

[0038] It should be noted that there is no specific limit on the number of layer structures, and the selection of each layer structure can be set to be consistent.

[0039] The preparation method of the ultra-high molecular weight polyethylene plate is as follows: each layer structure is flattened and evenly spread on the bottom of the mold frame according to the set thickness, then the mold is closed and pressurized, heated to 235°C, and kept at a constant temperature for 2 hours, followed by cooling and pressurization, with a pressure of ≥50Mpa per square centimeter, and demolding when the temperature drops to ≤50°C. When demolding, the mold frame is lifted, the plate body is taken out to remove the edge skin on the upper and lower sides, and then the plate body is placed in a cold press for shaping to obtain the ultra-high molecular weight polyethylene plate.

[0040] For example, an ultra-high molecular weight polyethylene plate with a three-layer structure has one layer made of modified ultra-high molecular weight polyethylene C, whose thickness is 2 / 5 of the thickness of the entire ultra-high molecular weight polyethylene plate; one layer is made of modified ultra-high molecular weight polyethylene B, whose thickness is 3 / 10 of the thickness of the entire ultra-high molecular weight polyethylene plate; and one layer is made of modified ultra-high molecular weight polyethylene A, whose thickness is 3 / 10 of the thickness of the entire ultra-high molecular weight polyethylene plate.

[0041] Specifically, the first layer is a heat-resistant, wear-resistant and pressure-resistant composite layer, the second layer is a wear-resistant and heat-resistant layer, the third layer is a heat-resistant layer, and the first layer and the third layer also have flame retardant properties.

[0042] Based on the above content, the present invention makes the following embodiment 1.

[0043] Weigh 24 parts by weight of ultra-high molecular weight polyethylene and 5.5 parts by weight of chlorinated polyethylene into a reaction pot equipped with a stirrer and a thermometer, add a certain amount of stearic acid and 0.5 parts by weight of calcium oxide, and then heat up. The controlled reaction temperature is 145°C and the reaction time is 2.0 hours. After the reaction is completed, discharge the material, cool it, and crush it to obtain modified ultra-high molecular weight polyethylene A; Weigh 28 parts by weight of ultra-high molecular weight polyethylene, 6.5 parts by weight of nitrided ultra-fine polyethylene powder, and 0.5 parts by weight of microcrystalline wax, put them into a high-speed mixer for fusion, heat the fusion temperature to 150°C, melt mix at high temperature to ensure that the two are fully mixed and uniform, and cool and solidify to obtain modified ultra-high molecular weight polyethylene B; Weigh 35 parts by weight of ultra-high molecular weight polyethylene, 35 parts by weight of modified ultra-high molecular weight polyethylene A, and 30 parts by weight of modified ultra-high molecular weight polyethylene B, then put them into a high-speed mixer for fusion. The fusion temperature is heated to 130°C. After the mixture is evenly mixed, cooled and solidified, modified ultra-high molecular weight polyethylene C can be obtained.

[0044] Then, the three polymer blends of modified ultra-high molecular weight polyethylene A, B and C are processed into materials. During processing, the modified ultra-high molecular weight polyethylene C is first spread on the bottom of the mold frame with a thickness of 4 / 10 and spread evenly; then the modified ultra-high molecular weight polyethylene B is spread with a thickness of 3 / 10 and spread evenly; the third layer is spread with a thickness of 3 / 10 and spread evenly, and then the mold is closed and pressurized, heated to 235°C, and kept at a constant temperature for 2 hours, followed by cooling and pressurization, with a pressure of ≥50Mpa per square centimeter. When the temperature drops to ≤50°C, the mold is removed. When removing the mold, the mold frame is lifted, the board body is taken out to remove the edge skin on the upper and lower sides, and then the board body is placed in a cold press for shaping to obtain an ultra-high molecular weight polyethylene board.

[0045] The performance of the ultra-high molecular weight polyethylene plate obtained in Example 1 was tested, and the data are shown in Table 1 below.

[0046] Table 1

[0047] As shown in Table 1, the tensile strength, elongation at break, impact strength, and ball indentation hardness of the ultra-high molecular weight polyethylene sheet are significantly better than the national standards, proving that the ultra-high molecular weight polyethylene sheet made from the modified ultra-high molecular weight polyethylene of the present invention has greatly improved mechanical properties due to the presence of the mesh structure. Secondly, the friction coefficient and wear rate are also significantly better than the national standards, the Vicat softening point is significantly better than the national standard, and the linear expansion coefficient is also better than the national standard, proving that the wear resistance and temperature resistance of the ultra-high molecular weight polyethylene sheet are also greatly improved on the basis of improved mechanical properties.

[0048] The present invention also provides Examples 2-4 and Comparative Examples 1-5.

[0049] The difference of Example 2 is that the modified ultra-high molecular weight polyethylene A contains 22 parts by weight of ultra-high molecular weight polyethylene and 7.5 parts by weight of chlorinated polyethylene; the modified ultra-high molecular weight polyethylene B contains 25 parts by weight of ultra-high molecular weight polyethylene and 9.5 parts by weight of nitrided ultrafine polyethylene powder.

[0050] Refer to the performance test of Example 1, and the test data of Example 2 is shown in Table 2.

[0051] Table 2

[0052] Example 3 The difference from Example 2 is that the ultra-high molecular weight polyethylene in the modified ultra-high molecular weight polyethylene C has a weight proportion of 25, the weight proportion of the modified ultra-high molecular weight polyethylene A has a weight proportion of 40, and the weight proportion of the modified ultra-high molecular weight polyethylene B has a weight proportion of 35.

[0053] Referring to the performance test of Example 1, the test data of Example 3 is shown in Table 3.

[0054] Table 3

[0055] Example 4 The difference from Example 2 is that the ultra-high molecular weight polyethylene in the modified ultra-high molecular weight polyethylene C has a weight proportion of 30, the modified ultra-high molecular weight polyethylene A has a weight proportion of 32, and the modified ultra-high molecular weight polyethylene B has a weight proportion of 38.

[0056] Referring to the performance test of Example 1, the test data of Example 4 is shown in Table 4.

[0057] Table 4

[0058] Based on the data of Example 1, combined with Examples 2-4, it can be seen that the mechanical properties and temperature parameters of Example 3 are the best, followed by Example 4, and then Example 2. It can be seen that the comprehensive wear resistance and temperature resistance of Example 3 are the most improved. Therefore, under the conditions of the reaction temperature and reaction time set by the present invention, the wear resistance and temperature resistance of the modified ultra-high molecular weight polyethylene can be improved to a certain extent under the conditions of different weight fractions, and the more modified ultra-high molecular weight polyethylene with a mesh structure, the better the wear resistance and temperature resistance of the ultra-high molecular weight polyethylene sheet.

[0059] Comparative Example 1 The difference from Example 1 is that the temperature in the modified ultra-high molecular weight polyethylene A is 120°C, the reaction time is 1 hour, and the temperature in the modified ultra-high molecular weight polyethylene B is 110°C.

[0060] Refer to the performance test of Example 1, and the test data of Comparative Example 1 is shown in Table 5.

[0061] Table 5

[0062] Comparative Example 2 The difference from Example 1 is that the reaction temperature of modified ultra-high molecular weight polyethylene A is 130°C and the reaction time is 1h; the reaction temperature of modified ultra-high molecular weight polyethylene B is 140°C; and the reaction temperature of modified ultra-high molecular weight polyethylene C is 120°C.

[0063] Refer to the performance test of Example 1, and the test data of Comparative Example 2 is shown in Table 6.

[0064] Table 6

[0065] It can be seen from Comparative Examples 1-2 that when the reaction temperature and reaction time in the production process of modified ultra-high molecular weight polyethylene are lower than the reaction temperature and reaction time set in the present invention, even if chlorinated polyethylene or ultrafine polyethylene powder is added to the ultra-high molecular weight polyethylene, the wear resistance and temperature resistance of the ultra-high molecular weight polyethylene plate cannot meet the standards.

[0066] Comparative Example 3 The difference from Example 1 is that no DC power supply with a voltage of 600 V is supplied during the nitridation treatment of the ultrafine polyethylene powder, and the pressure in the reactor does not increase.

[0067] Referring to the performance test of Example 1, the test data of Comparative Example 3 is shown in Table VII.

[0068] Table 7

[0069] It can be seen from Comparative Example 3 that the nitriding treatment of the ultrafine polyethylene powder did not undergo power supply and voltage boosting, and the temperature resistance and wear resistance of the modified ultra-high molecular weight polyethylene B prepared therefrom were not improved. Even if chlorinated polyethylene or ultra-fine polyethylene powder was added to the ultra-high molecular weight polyethylene, the wear resistance and temperature resistance of the ultra-high molecular weight polyethylene plate could not meet the standards, and the test data were worse than those of Comparative Examples 1 and 2.

[0070] Comparative Example 4 The difference from Example 1 is that during the nitridation treatment of the ultrafine polyethylene powder, the temperature is raised to 40°C.

[0071] Referring to the performance test of Example 1, the test data of Comparative Example 4 is shown in Table 8.

[0072] Table 8

[0073] Comparative Example 5 The difference from Example 1 is that during the nitridation treatment of the ultrafine polyethylene powder, the temperature is raised to 50°C.

[0074] Referring to the performance test of Example 1, the test data of Comparative Example 5 is shown in Table 9.

[0075] Table 9

[0076] As can be seen from Comparative Examples 4-5, the test data is better than Comparative Example 3, but worse than Comparative Examples 1-2. Since the nitriding temperature of the ultrafine polyethylene powder in Comparative Examples 4-5 is increased, the temperature resistance and wear resistance of the modified ultrahigh molecular weight polyethylene B prepared therefrom are improved compared to Comparative Examples 1-2, but the degree of improvement is not enough, and the wear resistance and temperature resistance of the ultrahigh molecular weight polyethylene sheet cannot reach the standard. Moreover, the test data of Comparative Examples 4-5 are also worse than those of Comparative Examples 1 and 2, which also shows that even if the ultrafine polyethylene powder used in Comparative Examples 4-5 is subjected to the corresponding nitriding treatment, the parameter setting of the nitriding treatment does not meet the parameters of the nitriding treatment in the present invention, and therefore the wear resistance and temperature resistance of the ultrahigh molecular weight polyethylene sheet cannot reach the standard.

[0077] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A process for enhancing the heat resistance and wear resistance of an ultra-high molecular weight polyethylene plate, wherein the raw material of the ultra-high molecular weight polyethylene plate is ultra-high molecular weight polyethylene, characterized in that: The reinforcing process comprises adding chlorinated polyethylene and / or ultrafine polyethylene powder to ultra-high molecular weight polyethylene, and blending the mixture with the additives under controlled temperature to form ultra-high molecular weight polyethylene with a network structure. The enhancement process includes the following three modes: Mode S1: Add chlorinated polyethylene to ultra-high molecular weight polyethylene, put it into a reaction pot equipped with a stirrer and a thermometer, add stearic acid and calcium oxide, heat and blend until the temperature reaches 140-150°C, the reaction time is 1.5-2.0h, and after blending, obtain modified ultra-high molecular weight polyethylene A; Mode S2: Adding ultrafine polyethylene powder that has been nitrided to ultra-high molecular weight polyethylene, adding microcrystalline wax and putting them into a high-speed mixer for fusion, heating the fusion temperature to 150°C, melting and mixing at high temperature, cooling and solidifying to obtain modified ultra-high molecular weight polyethylene B; Mode S3: Add modified ultra-high molecular weight polyethylene A and modified ultra-high molecular weight polyethylene B into ultra-high molecular weight polyethylene, and then put them into a high-speed mixer for fusion. The fusion temperature is heated to 130°C. After the mixture is evenly mixed, cooled and solidified, modified ultra-high molecular weight polyethylene C can be obtained.

2. The process for enhancing the heat resistance and wear resistance of ultra-high molecular weight polyethylene sheet according to claim 1, characterized in that: The nitriding treatment is specifically as follows: ultra-high molecular weight polyethylene is placed in a reactor and stirred, liquid ammonia is added, a DC power supply with a voltage of 600V is introduced, and at the same time, the pressure in the reactor is increased to 5MPa, and the temperature is controlled at 30°C, and then pure nitrogen is introduced at a flow rate of 5L / min. The nitrogen ions formed in the liquid nitrogen continuously combine with the ultra-high molecular weight polyethylene, and after cooling, fine particles of a preset particle size are screened out to obtain ultrafine polyethylene powder.

3. The process for enhancing the heat resistance and wear resistance of ultra-high molecular weight polyethylene sheet according to claim 1, characterized in that: The particle size of the ultrafine polyethylene powder is 100-130 mesh.

4. The process for enhancing the heat resistance and wear resistance of ultra-high molecular weight polyethylene sheet according to claim 1, characterized in that: The chlorinated polyethylene is prepared from high-density polyethylene through a chlorination substitution reaction.

5. An ultra-high molecular weight polyethylene plate, characterized in that: The ultra-high molecular weight polyethylene plate has a multi-layer structure, and its layer structure is made of one or more of modified ultra-high molecular weight polyethylene A, modified ultra-high molecular weight polyethylene B or modified ultra-high molecular weight polyethylene C obtained by the process for enhancing the heat resistance and wear resistance of the ultra-high molecular weight polyethylene plate described in claim 1.

6. The ultra-high molecular weight polyethylene plate according to claim 5, characterized in that: The layer structure of the ultra-high molecular weight polyethylene plate comprises at least three layers.

7. The ultra-high molecular weight polyethylene plate according to claim 6, characterized in that: When one layer of the ultra-high molecular weight polyethylene plate is made of modified ultra-high molecular weight polyethylene C, its thickness accounts for at least 2 / 5 of the thickness of the entire ultra-high molecular weight polyethylene plate.

8. A method for preparing an ultra-high molecular weight polyethylene sheet according to any one of claims 5 to 7, characterized in that: The preparation method is as follows: each layer structure is flattened and evenly spread on the bottom of the mold frame according to the set thickness, then the mold is closed and pressurized, heated to 235°C, and kept at a constant temperature for 2 hours, followed by cooling and pressurization, with a pressure of ≥50Mpa per square centimeter, and demolding is performed when the temperature drops to ≤50°C. When demolding, the mold frame is lifted, the plate body is taken out to remove the edge skin on the upper and lower sides, and then the plate body is placed in a cold press for shaping to obtain an ultra-high molecular weight polyethylene plate.

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