Thermoplastic elastomer and method for producing the same

Abstract

This application discloses a thermoplastic elastomer and its preparation method. The raw materials include ultra-high molecular weight polyethylene (UHMWPE), SEBS rubber, and a compatibilizer. The UHMWPE has a molecular weight greater than 200,000, and the compatibilizer is a mixture of styrene-maleic anhydride-acrylonitrile terpolymer and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer. This application uses a formulation of UHMWPE, SEBS rubber, and a compatibilizer to ensure that the material has low hardness while satisfying self-lubricating and high wear resistance, thus expanding the application scenarios of thermoplastic elastomers.

Description

Technical Field

[0001] This application relates to the field of polymer materials and engineering, and specifically to a thermoplastic elastomer and its preparation method. Background Technology

[0002] Self-lubricating thermoplastic elastomers are a class of polymeric materials that combine the processing characteristics of thermoplastics with the properties of elastomers. Their core feature is that they require little or no external lubricants such as greases or lubricants, and can significantly reduce the coefficient of friction and wear during the movement of friction pairs through the material's own intrinsic lubrication properties. At the same time, these materials can be melted, plasticized, and molded at high temperatures, while exhibiting rubber-like flexibility and resilience at room temperature. Therefore, they have broad application prospects in fields such as machinery manufacturing, automotive industry, and electronics.

[0003] Ultra-high molecular weight polyethylene (UHMWPE), as a special thermoplastic, has a significantly lower coefficient of friction and better wear resistance compared to ordinary polyethylene and other thermoplastic materials due to its molecular chain structure. It is one of the ideal base materials for preparing self-lubricating materials.

[0004] However, in existing technologies, the preparation of thermoplastic elastomers based on ultra-high molecular weight polyethylene (UHMWPE) typically employs a dynamic vulcanization process with EPDM rubber. While this process can reduce the material's hardness to meet elasticity requirements, it significantly diminishes the excellent self-lubricating properties of UHMWPE, failing to balance low hardness with high lubricity. Furthermore, dynamic vulcanization also suffers from high production costs and strong product odor, limiting its application in scenarios with stringent performance and environmental requirements.

[0005] Therefore, how to prepare low-hardness thermoplastic elastomers by improving formulations and processes while maintaining the self-lubricating properties and high wear resistance of ultra-high molecular weight polyethylene has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this application is to provide a thermoplastic elastomer that, while maintaining low hardness, has good self-lubricating properties and high wear resistance.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: a thermoplastic elastomer is provided, the raw materials for which include: ultra-high molecular weight polyethylene, SEBS rubber and a compatibilizer, wherein the ultra-high molecular weight polyethylene has a molecular weight greater than 200,000, and the compatibilizer is a mixture of styrene-maleic anhydride-acrylonitrile terpolymer and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer.

[0008] As a preferred embodiment, the styrene-maleic anhydride-acrylonitrile terpolymer and the maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer are mixed in a mass ratio of (1~2):1 to prepare the compatibilizer.

[0009] As another preferred embodiment, the SEBS rubber is a high molecular weight hydrogenated styrene-butadiene block copolymer and / or a low molecular weight hydrogenated styrene-butadiene block copolymer, wherein the high molecular weight hydrogenated styrene-butadiene block copolymer has a molecular weight of 250,000 to 350,000 l, and the low molecular weight hydrogenated styrene-butadiene block copolymer has a molecular weight of 50,000 to 80,000 l.

[0010] As another preferred embodiment, the high molecular weight hydrogenated styrene-butadiene block copolymer and the low molecular weight hydrogenated styrene-butadiene block copolymer are mixed in a mass ratio of (1~2):1 to prepare the SEBS rubber.

[0011] As another preferred option, the raw materials also include a scratch-resistant modifier, which is silicone oil and / or fumed silica.

[0012] Alternatively, the raw materials also include a filler oil with a viscosity of 40-50 mm. 2 / S.

[0013] As another preferred option, the raw materials also include other processing aids and carbon black, wherein the other processing aids include any one or more combinations of antioxidants, light stabilizers and slip agents.

[0014] As another preferred embodiment, the slip agent is a mixture of erucamide and titanium disulfide in a mass ratio of (1~2):3.

[0015] Further preferred, the raw materials, by weight, include: 30-40 parts of the ultra-high molecular weight polyethylene, 20-35 parts of the SEBS rubber, 20-35 parts of the filler oil, 5-7 parts of the scratch-resistant modifier, 5-7 parts of the compatibilizer, 1-2 parts of other processing aids, and 1-2 parts of carbon black.

[0016] This application also provides a method for preparing the above-mentioned thermoplastic elastomer, wherein the filler oil is mixed with the SEBS rubber to obtain a filler oil, the filler oil, the high molecular weight polyethylene, the scratch-resistant modifier, the compatibilizer, the other processing aids and the carbon black are mixed, melt-blended in a twin-screw extruder, and extruded to obtain the thermoplastic elastomer.

[0017] Compared with the prior art, the beneficial effects of this application are as follows:

[0018] (1) This application uses a formulation of ultra-high molecular weight polyethylene, SEBS rubber and compatibilizer to ensure that the material has low hardness while satisfying self-lubrication and high wear resistance, thus expanding the application scenarios of thermoplastic elastomers.

[0019] (2) The technical solution of this application adopts a multi-component melt blending preparation method, which avoids complex cross-linking reaction, reduces the special requirements for equipment, and physical blending reduces the use of high-cost vulcanizing agents. The product does not have the high odor problem caused by dynamic vulcanization and does not require additional deodorization treatment, further reducing production costs.

[0020] (3) The technical solution of this application achieves outstanding surface damage resistance of the product through the synergy of scratch-resistant modifier, filler oil and other components, and avoids the performance degradation problem caused by lubricant seepage during use. It takes into account both rigidity and toughness and can meet the long-term use needs of mechanical transmission, sealing parts and other scenarios. Detailed Implementation

[0021] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0023] This application provides a thermoplastic elastomer, the raw materials for which include: ultra-high molecular weight polyethylene, SEBS rubber and compatibilizer, wherein the compatibilizer is a mixture of styrene-maleic anhydride-acrylonitrile terpolymer (SAM) and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer.

[0024] This application utilizes the synergistic formulation of raw materials for thermoplastic elastomer preparation to obtain a thermoplastic elastomer that combines self-lubricating properties with low hardness and high wear resistance, without relying on external lubricants. This expands the application scenarios of thermoplastic elastomers in fields with high requirements for comprehensive material performance, such as mechanical transmission, sealing components, and consumer electronics.

[0025] Ultra-high molecular weight polyethylene (UHMWPE) has a molecular weight greater than 200,000. UHMWPE molecules have long, linear chains and weak intermolecular forces, making them prone to sliding under external forces and inherently possessing an extremely low coefficient of friction. This characteristic is the core basis for the material's ability to achieve low friction without relying on external lubricants, which helps meet the performance requirements for dynamic friction coefficient and mitigates the problem of polyethylene losing its self-lubricating properties in existing dynamic vulcanization technologies.

[0026] When subjected to friction, the ultra-long molecular chains of UHMWPE can absorb energy through orientation and slippage, reducing wear on the material surface. Its wear resistance is far superior to that of ordinary polyethylene and most thermoplastics. When blended with SEBS rubber, it can maintain elasticity while ensuring the material's wear resistance in long-term friction scenarios, thus contributing to the material's "high wear resistance" properties.

[0027] The high molecular weight of UHMWPE endows the material with a certain rigidity and strength. When blended with SEBS rubber and other flexible components, UHMWPE can serve as a "skeleton" support system to balance the strength reduction caused by the addition of SEBS and other flexible components, ensuring that the tensile strength of the material meets the requirements and preventing the blended system from losing structural stability due to excessive softening.

[0028] The SEBS rubber of this application is a hydrogenated styrene-butadiene block copolymer. SEBS rubber consists of hard styrene segments and soft hydrogenated butadiene segments. The hard segments form physical crosslinking points, while the soft segments provide elastic deformation capability, exhibiting rubber-like flexibility and resilience at room temperature. When blended with UHMWPE, SEBS effectively neutralizes the rigidity of UHMWPE, reducing the overall hardness of the material. Simultaneously, the molecular chain movement of the soft segments endows the material with excellent deformation recovery capability, enabling it to meet the deformation requirements of thermoplastic elastomers.

[0029] In a more preferred embodiment, the SEBS rubber comprises a mixture of a high molecular weight hydrogenated styrene-butadiene block copolymer and a low molecular weight hydrogenated styrene-butadiene block copolymer. The high molecular weight hydrogenated styrene-butadiene block copolymer has a molecular weight of 250,000 to 350,000, and the low molecular weight hydrogenated styrene-butadiene block copolymer has a molecular weight of 50,000 to 80,000. In some preferred embodiments, the high molecular weight hydrogenated styrene-butadiene block copolymer and the low molecular weight hydrogenated styrene-butadiene block copolymer are mixed in a mass ratio of (1 to 2):1 to obtain the SEBS rubber.

[0030] High molecular weight SEBS, due to its enhanced cross-linking structure and density of physical cross-linking points, can improve the elastic recovery rate and fatigue resistance of materials, making it suitable for applications requiring high durability. Medium molecular weight SEBS has better flowability, which can further improve processability and help to uniformly disperse low molecular weight components. The combination of the two can balance the mechanical stability and processing flowability of elastomers, which is a key support for achieving "low hardness and self-lubricating properties coexisting".

[0031] This application improves the interfacial compatibility between different components by adding a compatibilizer to the thermoplastic elastomer, thereby ensuring the uniformity and performance stability of the blend material. Specifically, the styrene segments in the styrene-maleic anhydride-acrylonitrile terpolymer can interact with the styrene segments of SEBS through compatibility, while the polar groups such as maleic anhydride and acrylonitrile can form weak polar adsorption or hydrogen bonding with the UHMWPE molecular chains, thus building a "bridge" between the two substrates, reducing interfacial defects, and improving the uniformity of the blend system.

[0032] Maleic anhydride-grafted hydrogenated styrene-butadiene block copolymers can achieve good compatibility with SEBS molecular chains through segment entanglement. At the same time, the grafted maleic anhydride groups are highly polar and can undergo esterification reactions or form hydrogen bonds with active groups such as hydroxyl groups at the ends or defects of UHMWPE molecular chains, further enhancing the interfacial adhesion between the two substrates and avoiding performance degradation caused by interfacial separation during processing or use of the blend.

[0033] This application uses a mixture of styrene-maleic anhydride-acrylonitrile terpolymer (SAM) and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer in a mass ratio of (1~2):1. Through different molecular structure designs, the compatibility of the multi-component raw materials is specifically improved from the perspectives of "polarity matching" and "structural similarity," avoiding the problem of insufficient effect of a single compatibilizer. Ultimately, this ensures that the blended material maintains low hardness and high elongation while also possessing excellent self-lubricating and wear-resistant properties.

[0034] The soft segment structure of SEBS can absorb energy through molecular chain entanglement and deformation, significantly improving the elongation of the blend system and compensating for the brittleness of UHMWPE due to its high molecular weight. At the same time, its hard segments have good compatibility with UHMWPE and compatibilizers, and can form a synergistic effect with UHMWPE, reducing hardness while avoiding excessive decrease in tensile strength, thus achieving a balance of "low hardness-high toughness-sufficient strength".

[0035] The raw materials for preparing the thermoplastic elastomer of this application also include a filler oil, which is paraffin oil. In some preferred embodiments, the viscosity of the filler oil is 40-50 mm. 2 / S, paraffin oil with a flash point of 200~230 °C. This application adds a filler oil to the thermoplastic elastomer. This filler oil can penetrate into the molecular chain gaps of SEBS rubber, weakening intermolecular forces, reducing the material's hardness and modulus, making the originally harder blend system easier to process, and ultimately giving the product a lower Shore hardness, meeting the thermoplastic elastomer's requirements for flexibility and resilience. Simultaneously, its good compatibility with SEBS prevents the material from losing elasticity due to excessive hardness.

[0036] UHMWPE, with its extremely high molecular weight, exhibits poor melt flowability, while SEBS rubber itself also possesses high viscosity. Filler oils reduce the melt viscosity of the blend, thereby enhancing the plasticizing effect and flow properties of the material in a twin-screw extruder, ensuring uniform mixing of all components, and reducing energy consumption and equipment load during processing.

[0037] High flash point paraffin oil is selected, which is not easy to volatilize or seep out during processing and use. It also has a certain degree of lubrication, which can work synergistically with the low friction characteristics of UHMWPE to help maintain the self-lubricating performance of the material and ensure that the dynamic friction coefficient meets the requirement of ≤0.6.

[0038] The addition of filler oil can appropriately reduce the tensile strength of the material, but can significantly improve the elongation. By balancing rigidity and toughness, the material can maintain high wear resistance while having better impact resistance and deformation recovery ability, thus meeting the comprehensive mechanical performance requirements in practical applications.

[0039] While filler oils are non-polar substances and have good compatibility with SEBS, they are prone to "oil leakage" when added in high proportions. The maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer used in this application has a hydrogenated butadiene segment structure similar to the hydrocarbon chain structure of paraffin oil. This allows it to adsorb filler oil molecules through intermolecular forces, reducing their migration tendency. Combined with its high flash point characteristic, this meets the "no oil leakage" requirement, ensuring the long-term self-lubricating properties of the material.

[0040] SEBS rubber exhibits excellent melt flow at high temperatures and superior compatibility with filler oils, reducing the mixing resistance of UHMWPE with other components. Its molecular chains can encapsulate and penetrate UHMWPE particles, promoting uniform dispersion of components under the shearing action of twin-screw extrusion and avoiding performance fluctuations caused by UHMWPE agglomeration.

[0041] The raw materials for preparing the thermoplastic elastomers of this application also include scratch-resistant modifiers, which primarily enhance the surface resistance to damage. In some embodiments, the scratch-resistant modifier is silicone oil and / or fumed silica. Silicone oil, as a liquid lubricant, can form a lubricating film on the material surface, reducing the frictional resistance between the friction pair and the material surface, reducing shear force during scratching, and thus mitigating surface damage. Fumed silica, as an inorganic nanoparticle, has high hardness and high dispersibility. When uniformly dispersed on the material surface and surface layer, it can form physical support points, enhancing surface wear resistance and resisting external forces from scratching the surface.

[0042] In some preferred embodiments, the scratch-resistant modifier is a mixture of silicone oil and fumed silica. The addition of fumed silica optimizes the microstructure of the material surface and reduces surface stickiness caused by the migration of SEBS rubber or filler oil; while the presence of silicone oil improves surface smoothness, enabling the material to maintain a stable feel and appearance during long-term use and avoiding surface roughening or performance degradation caused by scratch accumulation.

[0043] The silicone oil in the scratch-resistant modifier has good compatibility with SEBS rubber and filler oil, which can help improve the interfacial bonding between fumed silica and UHMWPE and SEBS, reduce processing defects caused by powder agglomeration, and ensure the uniformity of the overall material properties.

[0044] The raw materials for preparing the thermoplastic elastomer in this application also include carbon black, with a carbon black concentration of approximately 30% to 50%. Carbon black can be used primarily as a black pigment to uniformly color the material, meeting the product's color requirements. Furthermore, carbon black has a certain degree of conductivity; although the amount added is insufficient to make the material reach a conductive level, it can slightly reduce the surface resistance of the material. In certain scenarios where electrostatic sensitivity is a concern, this helps reduce the risks associated with static electricity accumulation.

[0045] Carbon black particles can be uniformly dispersed in blended systems, forming weak interfacial interactions with substrates such as UHMWPE and SEBS rubber. This interaction, to a certain extent, inhibits excessive molecular chain movement, helps improve the dimensional stability of the material, and reduces deformation caused by temperature changes or external forces. The addition of carbon black does not significantly affect the function of other key components in the system. Its surface properties are compatible with lubricants such as filler oils and silicone oils, and can synergistically maintain the processing stability and performance of the material.

[0046] The raw materials for preparing the thermoplastic elastomers of this application also include other processing aids, which may be, but are not limited to, antioxidants, light stabilizers, and slip agents. The antioxidant is a mixture of Chinox 626 and Chinox 445, mixed in a 1:1 mass ratio. The light stabilizer is a triazine derivative, such as UV-234.

[0047] The slip agent is a mixture of erucamide and titanium disulfide. In some preferred embodiments, erucamide and titanium disulfide are mixed in a 2:3 mass ratio to obtain the slip agent. Erucamide can reduce the coefficient of friction on the surface of polymer materials and improve the processing performance of the materials. Titanium disulfide is an inorganic compound with a special structure, possessing good lubricity and certain reinforcing properties. Its layered structure forms a sliding surface inside the material, effectively reducing internal friction, improving the self-lubricating properties of the material, and enhancing the mechanical properties of the material to a certain extent.

[0048] In some preferred embodiments, the raw materials for preparing the thermoplastic elastomer of this application, by weight, include: 30-40 parts of ultra-high molecular weight polyethylene, 20-35 parts of SEBS rubber, 20-35 parts of filler oil, 5-7 parts of scratch-resistant modifier, 5-7 parts of compatibilizer, 1-2 parts of other processing aids, and 1-2 parts of carbon black.

[0049] This application also provides a method for preparing a thermoplastic elastomer, wherein a filler oil is mixed with SEBS rubber to obtain a filler oil, and the filler oil, UHMWPE, scratch-resistant modifier, compatibilizer, other processing aids and carbon black are mixed, melt-blended in a twin-screw extruder, and extruded to obtain a thermoplastic elastomer.

[0050] The twin-screw extruder has an extrusion diameter of 50~80 mm, a length-to-diameter ratio of (50~60):1, a processing temperature of 150~210℃, a screw speed of 200~300 rpm, and a feeding speed of 200~300 rpm.

[0051] The technical solution of this application adopts a multi-component melt blending preparation method, which avoids complex cross-linking reactions, reduces special requirements for equipment, and physical blending reduces the use of high-cost vulcanizing agents. The product does not have the high odor problem caused by dynamic vulcanization and does not require additional deodorization treatment, further reducing production costs.

[0052] Example 1

[0053] By weight, the raw materials for preparing the thermoplastic elastomer of this application include: 30 parts ultra-high molecular weight polyethylene, 27.5 parts SEBS rubber, 27.5 parts filler oil, 5 parts scratch-resistant modifier, 7 parts compatibilizer, 2 parts other processing aids and 1 part carbon black, wherein the SEBS rubber is a low molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 60,000.

[0054] Specifically, the ultra-high molecular weight polyethylene (UHMWPE) has a molecular weight greater than 200,000, L5000, was purchased from Mitsui Chemicals, has a friction coefficient of 0.12, and an abrasion ratio of 50:10. -3 mm / kg·km; the filler oil is paraffin oil with a viscosity of 45 mm.2 / S, flash point is 210 ℃; scratch-resistant modifier is a mixture of silicone oil and fumed silica in a 1:1 mass ratio; compatibilizer is a mixture of ST-SAM4008 and MEB-7215 in a 1:1 mass ratio; other processing aids include antioxidants, light stabilizers and slip agents, the antioxidant is a mixture of Chinox 626 and Chinox 445 in a 1:1 mass ratio, the light stabilizer is UV-234, the slip agent is a mixture of erucamide and titanium disulfide in a 1:1 mass ratio; the carbon black is carrier-free carbon black with a concentration of 30%.

[0055] A thermoplastic elastomer was prepared using the above raw materials: the filler oil was mixed with SEBS rubber to obtain a filler oil, and the filler oil, UHMWPE, scratch-resistant modifier, compatibilizer, other processing aids and carbon black were mixed and melt-blended in a twin-screw extruder to obtain a thermoplastic elastomer.

[0056] The twin-screw extruder has an extrusion diameter of 63 mm, a length-to-diameter ratio of 56:1, a processing temperature of 150~210 ℃, a screw speed of 200~300 rpm, and a feeding speed of 200~300 rpm.

[0057] Example 2

[0058] 27.5 parts by weight of SEBS rubber were replaced with a high molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 300,000. Other preparation steps were the same as those in Example 1.

[0059] Example 3

[0060] The SEBS rubber was replaced with a mixture of 13.75 parts by weight of a high molecular weight hydrogenated styrene-butadiene block copolymer and 13.75 parts by weight of a low molecular weight hydrogenated styrene-butadiene block copolymer, wherein the high molecular weight hydrogenated styrene-butadiene block copolymer had a molecular weight of 300,000 and the low molecular weight hydrogenated styrene-butadiene block copolymer had a molecular weight of 60,000. Other preparation steps were consistent with those in Example 1.

[0061] Example 4

[0062] The amount of ultra-high molecular weight polyethylene added was adjusted to 25 parts by mass, the amount of low molecular weight hydrogenated styrene-butadiene block copolymer added was adjusted to 25 parts by mass, the amount of filler oil added was adjusted to 25 parts by mass, and the other preparation steps were consistent with the preparation steps in Example 1.

[0063] Example 5

[0064] The amount of ultra-high molecular weight polyethylene added was adjusted to 40 parts by mass, the amount of low molecular weight hydrogenated styrene-butadiene block copolymer added was adjusted to 25 parts by mass, the amount of filler oil added was adjusted to 25 parts by mass, no scratch-resistant modifier was added, and other preparation steps were consistent with the preparation steps in Example 1.

[0065] Example 6

[0066] No scratch-resistant agent was added, and the other preparation steps were consistent with those in Example 1.

[0067] Comparative Example 1

[0068] The ultra-high molecular weight polyethylene was replaced with high-density polyethylene 5000s with a molecular weight greater than 50,000 (Formosa Plastics). Other preparation steps remained consistent with those in Example 1.

[0069] Comparative Example 2

[0070] No compatibilizer was added, and the other preparation steps were consistent with those in Example 1.

[0071] Comparative Example 3

[0072] The compatibilizer was ST-SAM4008, a terpolymer of styrene-maleic anhydride-acrylonitrile, and the other preparation steps were consistent with those in Example 1.

[0073] Comparative Example 4

[0074] The compatibilizer was MEB-7215, a maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer. Other preparation steps were consistent with those in Example 1.

[0075] Comparative Example 5

[0076] The SEBS rubber was selected as 33.5 parts by weight of high molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 300,000. The amount of filler oil added was adjusted to 33.5 parts by weight. No scratch-resistant agent or compatibilizer was added. Other preparation steps were consistent with the preparation steps in Example 1.

[0077] Comparative Example 6

[0078] The ultra-high molecular weight polyethylene was adjusted to 30 parts by mass of high-density polyethylene 5000s, the SEBS rubber was selected as 30 parts by mass of high molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 300,000l, the amount of filler oil added was adjusted to 30 parts by mass, no compatibilizer was added, and the other preparation steps were consistent with the preparation steps in Example 1.

[0079] Comparative Example 7

[0080] The ultra-high molecular weight polyethylene was adjusted to 40 parts by mass of high-density polyethylene 5000s, the SEBS rubber was selected as 22.5 parts by mass of high molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 300,000, the amount of filler oil added was adjusted to 22.5 parts by mass, and the other preparation steps were consistent with the preparation steps in Example 1.

[0081] Performance testing

[0082] 1. Tensile strength test: According to ISO 37, 500 mm / min, the requirement is above 8MPa.

[0083] 2. Elongation test: According to ISO 37, 500 mm / min, the requirement is above 550%.

[0084] 3. Shore hardness test: According to ISO 868, take the reading in 15 seconds, Shore A, requirement <75A.

[0085] 4. Reciprocating Scraping Test: Using a quartz glass grinding head, with a load of 9 N, a reciprocating speed of 60 times / minute, and 1000 round trips, indentations are allowed, but scratches are not allowed.

[0086] 5. Dynamic friction test: According to TSM 1707G-2018, the speed is 100 nn / min, the load is 9.8 N, and the sliding friction coefficient is required to be below 0.6 compared with the quartz glass plate.

[0087] 6. Oil Exudation Test: Place a 12mm*12mm*2mm injection molded sample in an 80℃ oven for 48 hours. No oil exudation is required.

[0088] The thermoplastic elastomers prepared in each embodiment and each comparative example were subjected to the above-mentioned performance tests, and the test results are recorded in Table 1 below.

[0089] Table 1 Performance test results of each embodiment and each comparative example

[0090]

[0091] Analyzing the performance test results of Example 1, Comparative Example 1, and Comparative Example 2, this application uses ultra-high molecular weight polyethylene, SEBS rubber, and compatibilizer to obtain a thermoplastic elastomer with high tensile strength, low hardness, good wear resistance, and no oil exudation.

[0092] Analysis of the performance test results of Example 1, Comparative Example 3 and Comparative Example 4 shows that the compatibilizer selected in this application is a mixture of styrene-maleic anhydride-acrylonitrile terpolymer and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer, which can further obtain thermoplastic elastomers with better overall performance.

[0093] Analysis of the performance test results of Examples 1 to 3 shows that SEBS rubber, selected from a mixture of high molecular weight hydrogenated styrene-butadiene block copolymer and low molecular weight hydrogenated styrene-butadiene block copolymer, can obtain a thermoplastic elastomer with the best overall performance.

[0094] Analysis of the performance test results of Examples 1 and 6 shows that adding a scratch-resistant agent can further improve the tensile strength of thermoplastic elastomers, reduce friction marks, and reduce oil seepage.

[0095] In summary, this application uses a formulation of ultra-high molecular weight polyethylene, SEBS rubber, and compatibilizers to prepare thermoplastic elastomers. While ensuring that the material has low hardness, it also satisfies the requirements of self-lubrication and high wear resistance, expanding the application scenarios of thermoplastic elastomers. Moreover, the preparation method is simple and suitable for large-scale production.

[0096] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A thermoplastic elastomer, characterized by, By weight, the raw materials for preparation include: 30-40 parts ultra-high molecular weight polyethylene, 20-35 parts SEBS rubber, 20-35 parts filler oil, 5-7 parts scratch-resistant modifier, 5-7 parts compatibilizer, 1-2 parts other processing aids, and 1-2 parts carbon black. The ultra-high molecular weight polyethylene has a molecular weight greater than 200,000, and the compatibilizer is a mixture of styrene-maleic anhydride-acrylonitrile terpolymer and maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer in a mass ratio of (1~2):

1. The SEBS rubber is a low molecular weight hydrogenated styrene-butadiene block copolymer with a molecular weight of 50,000 to 80,000. The scratch-resistant modifier is a mixture of silicone oil and fumed silica in a mass ratio of 1:

1. The other processing aids include any one or more of antioxidants, light stabilizers, and slip agents.

2. The thermoplastic elastomer of claim 1, wherein, The viscosity of the filler oil is 40~50 mm. 2 / S.

3. The thermoplastic elastomer of claim 1, wherein, The slip agent is a mixture of erucamide and titanium disulfide in a mass ratio of (1~2):

3.

4. The method of preparing a thermoplastic elastomer according to any one of claims 1 to 3, wherein The filler oil is mixed with the SEBS rubber to obtain an oil-extended material. The oil-extended material, the high molecular weight polyethylene, the scratch-resistant modifier, the compatibilizer, the other processing aids and the carbon black are mixed and melt-blended in a twin-screw extruder and extruded to obtain the thermoplastic elastomer.

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