Scratch-resistant, reinforced thermoplastic elastomers and methods for making the same

Abstract

This invention relates to the field of TPV thermoplastic elastomer materials technology, specifically to a scratch-resistant, reinforced thermoplastic elastomer and its preparation method. The invention involves reacting a soluble divalent and trivalent metal salt solution, sodium dodecyl sulfate, an alkaline substance, and an alkyl thiophosphate or alkyl thiophosphate compound system to prepare a self-assembly self-lubricating modifier. This modifier is then dispersed in deionized water with a nonionic surfactant to form a uniform suspension. Hydroxyl-terminated polydimethylsiloxane and a crosslinking agent are added, followed by a condensation catalytic reaction to obtain a self-assembly self-lubricating modifier @PDMS core-shell composite powder. Polypropylene, the core-shell composite powder, a compatibilizer, and an antioxidant are premixed at room temperature, melt-plasticized, and then EPDM rubber and a dynamic crosslinking agent are added and shear-mixed to obtain a TPV blend. After hot pressing, holding pressure, cooling, and demolding, the target composite material is obtained. This material exhibits excellent scratch resistance, has a controllable preparation process, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of TPV thermoplastic elastomer material technology, specifically to a scratch-resistant, reinforced thermoplastic elastomer and its preparation method. Background Technology

[0002] Thermoplastic vulcanizate (TPV) is a thermoplastic elastomer that combines the elasticity of rubber with the plasticity of thermoplastic polymers, demonstrating significant advantages in the automotive, consumer electronics, and smart wearable device industries. Its excellent tactile feel (warm and smooth, with moderate damping) and weather and chemical resistance make it widely used in components such as automotive door armrests, wristbands, watch straps, headphone covers, and tool grips. It also possesses environmentally friendly characteristics such as lightweight design, ease of processing and molding, and recyclability, effectively reducing overall costs and increasing design freedom.

[0003] However, when TPV is used in decorative parts with higher requirements for appearance and durability, the following drawbacks exist: First, the tensile and impact strength of the material itself is relatively weaker than that of engineering plastics, and it may deform or be damaged in scenarios with large forces or frequent assembly; second, the surface hardness is usually insufficient, and the wear and scratch resistance is limited, making it easy to get scratches in daily use, affecting the aesthetics and texture. The above problems are the key bottlenecks for TPV in high-end visible parts applications. Summary of the Invention

[0004] The purpose of this invention is to provide a scratch-resistant, reinforced thermoplastic elastomer and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a scratch-resistant and reinforced thermoplastic elastomer, comprising the following steps: Step 1: A soluble divalent metal salt solution and a soluble trivalent metal salt solution are slowly added to a sodium dodecyl sulfate (SDS) solution to form a mixed solution. An appropriate amount of alkaline substance is added, and the mixture is stirred continuously at room temperature for 3 hours. Subsequently, alkyl thiophosphate or alkyl thiophosphate is added to the mixed solution, and a hydrothermal reaction is carried out under continuous stirring. After the reaction is completed, the product is filtered to obtain the product, washed with a large amount of distilled water, and finally dried under vacuum to obtain a self-assembled self-lubricating modifier. Further, the amounts of each component in step 1 are as follows: 100 parts by mass of divalent metal salt, 20-70 parts by mass of trivalent metal salt, 10-30 parts by mass of sodium dodecyl sulfate, 20-45 parts by mass of alkyl thiophosphate or alkyl thiophosphate, and 50-200 parts by mass of alkaline substance.

[0006] Furthermore, the hydrothermal reaction is carried out at a temperature of 60~110℃ for 10~24h, and the pH of the reaction system is 7~10. Furthermore, the cation in the soluble divalent metal solution is Cu. 2+ Zn 2+ Ni 2+ Mg 2+ Any one or more of the following; the anion is NO3. - SO4 2- Any one or more of the following.

[0007] Furthermore, the cation in the soluble trivalent metal solution is Fe. 3+ Al 3+ Any one or more of the following, with NO3 as the anion. - SO4 2- Any one or more of the following.

[0008] Furthermore, the alkaline substance is any one or more of urea, ammonia, and sodium hydroxide.

[0009] Further, the alkyl thiophosphate or alkyl thiophosphate is any one of O,O-diethyl dithiophosphate, O,O-di-n-butyl dithiophosphate, O,O-diethyl dithiophosphate sodium, O,O-diethyl dithiophosphate potassium, O,O-di-n-butyl dithiophosphate sodium, and O,O-di-n-butyl dithiophosphate zinc.

[0010] Step 2: In a three-necked flask equipped with a mechanical stirrer, condenser, and thermometer, add deionized water, self-assembling self-lubricating modifier, and nonionic surfactant in sequence. Start stirring and heat to 50-70°C, maintaining a stirring speed of 300-500 r / min for 30-60 min until a homogeneous and stable suspension is formed. Then, add hydroxyl-terminated polydimethylsiloxane and crosslinking agent to the suspension and continue stirring for 10-20 min to initially disperse the organic phase in the aqueous phase. Next, add a condensation reaction catalyst to the mixture and heat to 70-85°C for 2-5 h. After the reaction, allow the emulsion to cool naturally to room temperature, centrifuge the emulsion, wash the precipitate 2-3 times alternately with deionized water and ethanol, and then vacuum dry at 60-80°C for 6-12 h to obtain self-assembling self-lubricating modifier@PDMS core-shell structure composite material powder. Further, the amounts of each component in step 2 are as follows: 100 parts by mass of deionized water, 0.5 to 5 parts by mass of self-assembly type self-lubricating modifier, 0.1 to 2 parts by mass of nonionic surfactant, 5 to 20 parts by mass of hydroxyl-terminated polydimethylsiloxane, 0.5 to 4 parts by mass of crosslinking agent, and 0.01 to 0.1 parts by mass of condensation reaction catalyst; Furthermore, the nonionic surfactant is one or more of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, polyoxyethylene laurate, and polyoxyethylene lauryl alcohol.

[0011] Furthermore, the catalyst for the condensation reaction is any one or more of dibutyltin dilaurate, dibutyltin diacetate, and stannous octoate.

[0012] Furthermore, the molecular weight range of hydroxyl-terminated polydimethylsiloxane is 800~10000 g / mol.

[0013] Furthermore, the crosslinking agent is one or more of tetraethyl orthosilicate, methyl orthosilicate, and methyltrimethoxysilane.

[0014] Step 3: Premix the dried polypropylene, self-assembling self-lubricating modifier @PDMS, compatibilizer, and antioxidant in a high-speed mixer at room temperature for 3-5 minutes. Then, add the premix to a mixer or twin-screw extruder and melt-plasticize it at a temperature of 170-190℃ and a speed of 40-80 rpm. After complete melting, add EPDM rubber and dynamic crosslinking agent and shear-mix for 5-15 minutes to obtain TPV blend. Place the TPV blend in a flat vulcanizing mold preheated to 180-190℃ and hot-press it under a pressure of 10-20 MPa for 5-15 minutes. Then, hold the pressure and cool to below room temperature. Demolding yields the scratch-resistant reinforced TPV composite material.

[0015] Furthermore, in step 3, the amount of each component in the TPV blend by weight percentage is as follows: 40-60% polypropylene, 40-60% EPDM rubber, 1-10% self-assembling self-lubricating modifier @PDMS, 1-5% dynamic crosslinking agent, 2-8% compatibilizer, and 0.1-0.5% antioxidant.

[0016] Furthermore, the dynamic crosslinking agent is any one or more of alkylphenol resin, dicumyl peroxide, di-tert-butyl peroxide, and benzoyl peroxide.

[0017] Furthermore, the compatibilizer is any one or more of ethylene-vinyl acetate copolymer, ethylene-propylene-diene monomer copolymer, and styrene-ethylene-butadiene-styrene copolymer.

[0018] Furthermore, the antioxidant includes one or more of the following: pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-1,6-hexylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], n-octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], and 2,2'-methylenebis(4-methyl-6-tert-butylphenol].

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are: the present invention provides a scratch-resistant and enhanced thermoplastic elastomer and its preparation method, providing a solution to the problem of easy scratching and damage when traditional TPV materials are used in automotive exterior parts.

[0020] In this invention, hydrotalcite (LDH) is a layered bimetallic hydroxide with positively charged layers and anion-exchangeable interlayers, thus possessing excellent intercalation and loading capabilities. LDH is modified using sodium dodecyl sulfate (SDS) to expand the interlayer spacing and enhance hydrophobicity through anion exchange, creating a more relaxed interfacial environment for subsequent intercalation. Based on the SDS-modified LDH structure, alkyl thiophosphates or alkyl thiophosphates are further inserted, effectively introducing phosphorus and sulfur-containing organic functional groups. These groups can form a self-lubricating transfer film during matrix friction, significantly improving the material's scratch resistance. Furthermore, LDH's unique nanosheet structure can be uniformly dispersed in the plastic matrix, forming physical cross-linking points. Through intercalation or exfoliation, it generates strong interfacial interactions with polymer molecular chains, effectively transferring and dispersing stress, thereby improving the material's strength, stiffness, and dimensional stability. Meanwhile, alkyl thiophosphates or alkyl thiophosphates such as O,O-diethyl dithiophosphate (DDP) contain the polar group -P(S)(OC2H5)2, which can form weak interactions with polar segments in the TPV matrix (such as the ethylene-propylene chain of EPDM), further enhancing the interfacial bonding between LDH and the matrix. Hydroxyl-terminated polydimethylsiloxanes are typical organosilicon elastomers with characteristics such as low modulus, high elastic recovery rate, and low surface energy. Coating the surface of SDS and DDP-modified LDH with a hydroxyl-terminated polydimethylsiloxane elastomer layer via in-situ emulsion polymerization not only improves the dispersibility and interfacial compatibility of LDH in the polymer matrix, but also, due to the inherent flexibility and hydrophobicity of the hydroxyl-terminated polydimethylsiloxane, endows the composite particles with better stress buffering and surface migration capabilities. By applying the multi-layered composite modifier to thermoplastic vulcanizates (TPVs), the rigidity enhancement effect of LDH and the friction reduction properties of DDP are combined to improve the scratch resistance of TPVs. On the other hand, the PDMS coating layer forms a flexible interface with the TPV matrix, which improves the mechanical properties of TPVs while avoiding the embrittlement problem caused by the agglomeration of LDH fillers. Ultimately, the scratch resistance, self-lubrication, and mechanical strength of TPV materials are optimized simultaneously. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] All materials used in this invention are commercially available products, among which O,O-diethyl dithiophosphate (CAS No. 298-06-6) is from Shanghai Maclean Biochemical Technology Co., Ltd. Example 1: A method for preparing a scratch-resistant, reinforced thermoplastic elastomer, comprising the following steps: Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3, 15 parts by mass of sodium dodecyl sulfate, and 50 parts by mass of urea to 5000 parts by mass of distilled water. Stir continuously at 35°C for 3 hours to obtain a mixed solution. Then add 20 parts by mass of O,O-diethyl dithiophosphate (DDP) to the mixed solution. Perform a hydrothermal reaction at 60°C and pH=7 for 10 hours with continuous stirring. After the reaction is completed, filter to obtain the product, wash with a large amount of distilled water, and finally dry under vacuum for 12 hours to obtain the self-assembled self-lubricating modifier SDS-DDP-LDH. Step 2: In a three-necked flask equipped with a mechanical stirrer, condenser, and thermometer, add the following in sequence: 100 parts by mass of deionized water, 2 parts by mass of SDS-DDP-LDH, and 1 part by mass of surfactant (nonylphenol polyoxyethylene ether). Start stirring and heat to 60°C, maintaining a stirring speed of 400 rpm for 50 minutes until a homogeneous and stable suspension is formed. Then add 15 parts by mass of hydroxyl-terminated polydimethylsiloxane (1000 g / mol) and 3 parts by mass of crosslinking agent tetraethyl orthosilicate to the suspension, and continue stirring for 15 minutes to initially disperse the organic phase in the aqueous phase. Subsequently, 0.05 parts by mass of dibutyltin dilaurate, a condensation reaction catalyst, were added to the mixed system, and the temperature was raised to 80°C for 4 hours. After the reaction was completed, the emulsion was naturally cooled to room temperature. The emulsion was then centrifuged and the precipitate was washed three times with deionized water and ethanol alternately. The precipitate was then vacuum dried at 70°C for 8 hours to obtain the final SDS-DDP-LDH@PDMS core-shell composite material powder. Step 3: 48 parts by weight of dried polypropylene, 5.5 parts by weight of SDS-DDP-LDH@PDMS, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. After 10 minutes, the mixture is discharged to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0023] Example 2: This example provides a method for preparing a scratch-resistant and reinforced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 10 parts by mass and the amount of O,O-diethyl dithiophosphate is 20 parts by mass; in step 2, the amount of SDS-DDP-LDH is 0.5 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 10 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 2 parts by mass.

[0024] Example 3: This example provides a method for preparing a scratch-resistant and reinforced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 20 parts by mass and the amount of O,O-diethyl dithiophosphate is 40 parts by mass; in step 2, the amount of SDS-DDP-LDH is 4 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 18 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 8 parts by mass.

[0025] Comparative Example 1: Compared with Example 1, the difference is that step 1 does not require intercalation modification of LDH with SDS and DDP, and the PDMS coating of LDH surface in step 2 is not performed.

[0026] Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3 and 50 parts by mass of urea to 5000 parts by mass of distilled water. The mixture is continuously stirred at 60℃ and pH=7 for 10 hours for hydrothermal reaction. After the reaction is completed, the product is filtered and washed with a large amount of distilled water. Finally, LDH is obtained by vacuum drying for 12 hours. Step 2: 48 parts by weight of dried polypropylene, 5.5 parts by weight of LDH, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. The mixture is discharged after 10 minutes to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0027] Comparative Example 2: Compared to Example 1, SDS-LDH was not modified by DDP intercalation in step 1, and the PDMS coating on the surface of SDS-LDH was not performed as in step 2.

[0028] Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3 and 15 parts by mass of sodium dodecyl sulfate to 5000 parts by mass of distilled water. The mixture is continuously stirred at 60℃ and pH=7 for 10 hours for hydrothermal reaction. After the reaction is completed, the product is filtered and washed with a large amount of distilled water. Finally, the product is obtained by vacuum drying for 12 hours.

[0029] Step 2: 48 parts by weight of dried polypropylene, 5.5 parts by weight of SDS-LDH, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. After 10 minutes, the mixture is discharged to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0030] Comparative Example 3: Compared to Example 1, DDP-LDH was not modified by SDS intercalation in step 1, and the surface of DDP-LDH was not coated with PDMS as in step 2.

[0031] Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3, and 20 parts by mass of O,O-diethyl dithiophosphate to 5000 parts by mass of distilled water. The mixture is continuously stirred and subjected to a hydrothermal reaction at 60℃ and pH=7 for 10 hours. After the reaction is completed, the product is filtered and washed with a large amount of distilled water. Finally, the product is obtained by vacuum drying for 12 hours.

[0032] Step 2: 48 parts by weight of dried polypropylene, 5.5 parts by weight of DDP-LDH, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. After 10 minutes, the mixture is discharged to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0033] Comparative Example 4: Compared to Example 1, the PDMS coating on the surface of SDS-DDP-LDH in step 2 was not performed.

[0034] Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3, 15 parts by mass of sodium dodecyl sulfate, and 50 parts by mass of urea to 5000 parts by mass of distilled water. Stir continuously at 35°C for 3 hours to obtain a mixed solution. Then add 20 parts by mass of O,O-diethyl dithiophosphate to the mixed solution and carry out a hydrothermal reaction at 60°C and pH=7 for 10 hours with continuous stirring. After the reaction is completed, filter to obtain the product, wash with a large amount of distilled water, and finally dry under vacuum for 12 hours to obtain the self-assembled self-lubricating modifier SDS-DDP-LDH.

[0035] Step 2: 48 parts by weight of dried polypropylene, 5.5 parts by weight of SDS-DDP-LDH, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. The mixture is discharged after 10 minutes to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0036] Comparative Example 5: Compared to Example 1, SDS-LDH was not modified by DDP intercalation in step 1.

[0037] Step 1: Add 100 parts by mass of CuSO4, 20 parts by mass of Al2(SO4)3, and 20 parts by mass of sodium dodecyl sulfate to 5000 parts by mass of distilled water. The mixture is continuously stirred at 60℃ and pH=7 for 10 hours for hydrothermal reaction. After the reaction is completed, the product is filtered and washed with a large amount of distilled water. Finally, the product is obtained by vacuum drying for 12 hours.

[0038] Step 2: In a three-necked flask equipped with a mechanical stirrer, condenser, and thermometer, add the following in sequence: 100 parts by mass of deionized water, 2 parts by mass of SDS-LDH, and 1 part by mass of surfactant (nonylphenol polyoxyethylene ether). Start stirring and heat to 60°C, maintaining a stirring speed of 400 rpm for 50 minutes until a homogeneous and stable suspension is formed. Then add 15 parts by mass of hydroxyl-terminated polydimethylsiloxane (1000 g / mol) and 3 parts by mass of crosslinking agent tetraethyl orthosilicate to the suspension, and continue stirring for 15 minutes to initially disperse the organic phase in the aqueous phase. Subsequently, 0.05 parts by mass of dibutyltin dilaurate, a condensation reaction catalyst, were added to the mixed system, and the temperature was raised to 80°C for 4 hours. After the reaction was completed, the emulsion was naturally cooled to room temperature. The emulsion was then centrifuged and the precipitate was washed three times alternately with deionized water and ethanol. Finally, it was vacuum dried at 70°C for 8 hours to obtain the final SDS-LDH@PDMS core-shell composite material powder.

[0039] Step 3: 48 parts by weight of dried polypropylene, 5.5 parts by weight of SDS-LDH@PDMS, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are premixed at room temperature for 3 minutes in a high-speed mixer. The premix is ​​then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) are added for high-intensity shear mixing. After 10 minutes, the mixture is discharged to obtain the TPV blend. The TPV blend is then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product is demolded to obtain the finished product.

[0040] Comparative Example 6: Compared to Example 1, the composite modifier SDS-DDP-LDH@PDMS was not added in step 3.

[0041] 53.5 parts by weight of dried polypropylene, 3 parts by weight of compatibilizer EVA (ethylene-vinyl acetate copolymer), and 0.5 parts by weight of antioxidant pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] were premixed at room temperature for 3 minutes in a high-speed mixer. The premix was then added to an internal mixer and melt-plasticized at 190°C and 60 rpm. After complete melting, 40 parts by weight of EPDM and 3 parts by weight of dynamic crosslinking agent dicumyl peroxide (DCP) were added for high-intensity shear mixing. The mixture was discharged after 10 minutes to obtain the TPV blend. The TPV blend was then placed in a flat vulcanizing mold preheated to 180°C and hot-pressed at 15 MPa for 15 minutes. After holding the pressure and cooling to below room temperature, the product was demolded to obtain the finished product.

[0042] Comparative Example 7: This embodiment provides a method for preparing a scratch-resistant, enhanced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 15 parts by mass, and the amount of O,O-diethyl dithiophosphate is 15 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass, and the amount of hydroxyl-terminated polydimethylsiloxane is 15 parts by mass; in step 3, the amount of SDS-DDP-LDH@PDMS is 5.5 parts by mass.

[0043] Comparative Example 8: This embodiment provides a method for preparing a scratch-resistant and reinforced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 15 parts by mass and the amount of O,O-diethyl dithiophosphate is 20 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 2 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 5.5 parts by mass.

[0044] Comparative Example 9: This embodiment provides a method for preparing a scratch-resistant and reinforced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 15 parts by mass and the amount of O,O-diethyl dithiophosphate is 20 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 15 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 0.5 parts by mass.

[0045] Comparative Example 10: This embodiment provides a method for preparing a scratch-resistant, enhanced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 15 parts by mass and the amount of O,O-diethyl dithiophosphate is 45 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 15 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 5.5 parts by mass.

[0046] Comparative Example 11: This embodiment provides a method for preparing a scratch-resistant, enhanced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 15 parts by mass and the amount of O,O-diethyl dithiophosphate is 20 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 15 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 15 parts by mass.

[0047] Comparative Example 12: This embodiment provides a method for preparing a scratch-resistant, enhanced thermoplastic elastomer, which differs from Example 1 in that: in step 1, the amount of sodium dodecyl sulfate is 5 parts by mass and the amount of O,O-diethyl dithiophosphate is 20 parts by mass; in step 2, the amount of SDS-DDP-LDH is 2 parts by mass and the amount of hydroxyl-terminated polydimethylsiloxane is 15 parts by mass; and in step 3, the amount of SDS-DDP-LDH@PDMS is 5.5 parts by mass.

[0048] The materials of the above embodiments and comparative examples were tested according to the following standards: (1) Friction coefficient: The dynamic friction coefficient μk is calculated with reference to GB / T10006-2021. The total mass of the slider is 200g±5g, the stretching speed is 100mm / min±10mm / min, and the grinding surface is TPV itself.

[0049] (2) Scratch Resistance Test: Refer to TM-5010 version 01 section 3.5.2, ISO 1518-1:2019(E) standard requirements. Record the minimum load at which the material shows scratches. Scratch head material: graphite round head. Scratch head diameter: 0.75mm; speed: (35±5)mm / s; scratch distance: 40mm. Requirement: Obvious material damage.

[0050] (3) Tensile test: the tensile strength of the material under the condition of 500 mm / min as required by ISO 37.

[0051] (4) Surface hardness: The surface hardness of the material under 15sec conditions as required by ISO 868.

[0052] (5) Elongation at break: Measured at 500 mm / min in accordance with the requirements of ISO 37.

[0053] The experimental results are shown in Table 1 below: Table 1

[0054] As shown in Examples 1-3 and Comparative Example 6, the strength and scratch resistance of the TPV material modified with SDS-DDP-LDH@PDMS are significantly improved.

[0055] As can be seen from Comparative Examples 1 and 2 and Example 1, the wear resistance of the material does not change significantly with the unmodified LDH modifier. The strength of the material increases slightly.

[0056] As can be seen from Comparative Example 3 and Example 1, LDH without SDS intercalation modification has limited effect on improving material strength and wear resistance.

[0057] As can be seen from Comparative Example 4 and Example 1, LDH without PDMS coating has limited effect on improving material strength and wear resistance, which is attributed to the characteristic that LDH is prone to agglomeration.

[0058] As can be seen from Comparative Example 6 and Example 1, the wear resistance of LDH material is only slightly improved without DDP intercalation modification.

[0059] As can be seen from Comparative Example 7, when the DDP content is less than the preferred ratio, the improvement in wear resistance and scratch resistance of the modified TPV material is limited, but the introduction of LDH still has a certain effect on improving the strength of TPV.

[0060] As can be seen from Comparative Example 8, when the PDMS content is less than the preferred ratio, the improvement in strength and scratch resistance of the modified TPV material is limited. The main reason may be that LDH without PDMS coating is prone to agglomeration, which affects the modification effect.

[0061] As can be seen from Comparative Example 9, the proportion of SDS-DDP-LDH@PDMS added was less than the optimal proportion, and the modification effect was not obvious.

[0062] Comparative Examples 10 and 11 show that when the content of DDP and SDS-DDP-LDH@PDMS is higher than the preferred ratio, the material strength will decrease.

[0063] As can be seen from Comparative Example 12, if the amount of SDS added is too small, the interlayer spacing of LDH cannot be fully opened, making it difficult for DDP to be intercalated, thus limiting the improvement of wear resistance of the modified TPV material.

[0064] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a scratch-resistant, reinforced thermoplastic elastomer, characterized in that: Includes the following steps: Step 1: Slowly add a soluble divalent metal salt solution and a soluble trivalent metal salt solution to a sodium dodecyl sulfate solution, an alkaline substance, an alkyl thiophosphate ester, or an alkyl thiophosphate. React under continuous stirring. After the reaction is complete, filter to obtain the product, wash with a large amount of distilled water, and finally dry under vacuum to obtain a self-assembled self-lubricating modifier. The alkaline substance is any one or more of urea, ammonia, and sodium hydroxide. Step 2: In a three-necked flask equipped with a mechanical stirrer, a condenser and a thermometer, add the following in sequence: deionized water, self-assembling self-lubricating modifier and nonionic surfactant, and stir to form a homogeneous and stable suspension. Subsequently, hydroxyl-terminated polydimethylsiloxane and a crosslinking agent were added to the suspension, and stirring was continued to initially disperse the organic phase in the aqueous phase. Then, a condensation reaction catalyst was added to the mixture to carry out the reaction. After the reaction was completed, the mixture was naturally cooled, and the above emulsion was centrifuged, washed alternately with deionized water and ethanol, and vacuum dried to obtain the self-assembled self-lubricating modifier @PDMS core-shell structure composite material powder. Step 3: Premix the dried polypropylene, self-assembling self-lubricating modifier @PDMS, compatibilizer and antioxidant in a high-speed mixer at room temperature. Then add the premix to a mixer or twin-screw extruder for melt plasticization. After complete melting, add EPDM rubber and dynamic crosslinking agent for shear mixing. The TPV blend is then discharged. The TPV blend is placed in a flat vulcanizing mold for hot pressing, followed by holding pressure and cooling before demolding to obtain the finished product.

2. The preparation method according to claim 1, characterized in that: The amounts of each component in step 1 are as follows: 100 parts by mass of divalent metal salt, 20-70 parts by mass of trivalent metal salt, 10-30 parts by mass of sodium dodecyl sulfate, 20-45 parts by mass of alkyl thiophosphate or alkyl thiophosphate, and 50-200 parts by mass of alkaline substance.

3. The preparation method according to claim 1, characterized in that: In step 1, the cation in the soluble divalent metal solution is Cu. 2+ Zn 2+ Ni 2+ Mg 2+ Any one or more of the following; the anion is NO3. - SO4 2- Any one or more of the following; the cation in the soluble trivalent metal solution is Fe. 3+ Al 3+ Any one or more of the following, with NO3 as the anion. - SO4 2- Any one or more of the following; the alkyl thiophosphate or alkyl thiophosphate is any one of O,O-diethyl dithiophosphate, O,O-di-n-butyl dithiophosphate, O,O-diethyl dithiophosphate sodium, O,O-diethyl dithiophosphate potassium, O,O-di-n-butyl dithiophosphate sodium, and O,O-di-n-butyl dithiophosphate zinc.

4. The preparation method according to claim 1, characterized in that: The amounts of each component in step 2 are as follows: 100 parts by mass of deionized water, 0.5 to 5 parts by mass of self-assembling self-lubricating modifier, 0.1 to 2 parts by mass of nonionic surfactant, 5 to 20 parts by mass of hydroxyl-terminated polydimethylsiloxane, 0.5 to 4 parts by mass of crosslinking agent, and 0.01 to 0.1 parts by mass of condensation reaction catalyst.

5. The preparation method according to claim 1, characterized in that: In step 2, the nonionic surfactant is one or more of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, polyoxyethylene laurate, and lauryl alcohol polyoxyethylene ether; the condensation reaction catalyst is one or more of dibutyltin dilaurate, dibutyltin diacetate, and stannous octoate; and the crosslinking agent is one or more of tetraethyl orthosilicate, methyl orthosilicate, and methyltrimethoxysilane.

6. The preparation method according to claim 1, characterized in that: In step 2, the molecular weight range of the hydroxyl-terminated polydimethylsiloxane is 800~10000 g / mol.

7. The preparation method according to claim 1, characterized in that: In step 3, the components in the TPV blend are expressed as follows by weight percentage: 40-60% polypropylene, 40-60% EPDM rubber, 1-10% self-assembling self-lubricating modifier @PDMS, 1-5% dynamic crosslinking agent, 2-8% compatibilizer, and 0.1-0.5% antioxidant.

8. The preparation method according to claim 1, characterized in that: In step 3, the dynamic crosslinking agent is any one or more of alkylphenol resin, dicumyl peroxide, di-tert-butyl peroxide, and benzoyl peroxide; the compatibilizer is any one or more of ethylene-vinyl acetate copolymer, ethylene-propylene-diene monomer copolymer, and styrene-ethylene-butadiene-styrene copolymer; and the antioxidant is any one or more of pentaerythritol tetrakis[methyl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-1,6-hexylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], and 2,2'-methylenebis(4-methyl-6-tert-butylphenol).

9. The scratch-resistant, reinforced thermoplastic elastomer prepared by the method according to any one of claims 1 to 8.

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