High-resilience self-lubricating tpe material, its preparation method and use

Abstract

The application discloses a kind of high resilience, self-lubricating TPE material and its preparation method and purposes, belong to elastomer material field.Firstly, SEBS and SEPS are mixed, and naphthenic oil is added to swell to obtain swelling matrix;Then, the swelling matrix, maleic anhydride, styrene, initiator and antioxidant are put into extruder, and maleic anhydride grafted SEBS is obtained by extrusion;Then, maleic anhydride grafted SEBS, 3-APBA-Bnpg is put into extruder to react, and aminopropyl single-end-capped PDMS is continuously added, and neopentyl glycol borate group-silicone co-grafted SEBS is obtained by extrusion;Finally, neopentyl glycol borate group-silicone co-grafted SEBS, hydroxypropyl end-capped PDMS, single-end hydroxyl perfluoropolyether, amino-modified SiO2 and hydrolysis-resistant agent are put into extruder, and after vacuum devolatilization extrusion, cooling, shaping, granulation is obtained.The TPE material provided by the application has excellent lubricity, resilience and hydrolysis resistance.

Description

Technical Field

[0001] This invention relates to the field of elastomer materials, specifically to a high-resilience, self-lubricating TPE material, its preparation method, and its applications. Background Technology

[0002] Thermoplastic elastomers (TPEs), especially oil-extended systems of hydrogenated styrene block copolymers (SEBS / SEPS), are widely used in automotive sealing, industrial vibration damping, consumer electronics, and food machinery due to their combination of rubber elasticity and thermoplastic processability. In these applications, materials not only require excellent elastic recovery to maintain long-term sealing and cushioning performance, but also low-friction surfaces to reduce motion resistance, suppress stick-slip noise, and minimize wear. However, in existing technologies, high resilience typically relies on chemical cross-linking to lock the molecular chain network, while self-lubrication often depends on the continuous migration and precipitation of small-molecule lubricants to the surface. These two aspects are mutually exclusive in terms of processing mechanisms and service behavior, making it difficult for existing materials to simultaneously achieve stable elastic recovery and long-term low-friction properties within the same system.

[0003] Currently, the industry mainly adopts several technical routes to overcome the above-mentioned technical problems, but all of them have some drawbacks. First, the permanent crosslinking of SEBS with peroxides (such as DCP) and co-crosslinking agents (such as TAIC) can achieve low compression set and high resilience, but the crosslinking reaction is irreversible. Scrap materials and scrap parts cannot be melted down and recycled, resulting in serious resource waste and environmental pressure. Furthermore, the permanently crosslinked system cannot be reconstructed after wear to regenerate the lubricating layer. Second, the use of physically blended methyl silicone oil or polyether-modified silicone oil as a lubricant can achieve a low coefficient of friction in the initial stage, but the silicone oil has poor compatibility with the SEBS matrix. During service, it continuously migrates and precipitates, not only contaminating the contact surface and affecting the cleanliness of food and medical settings, but also rapidly depleting the surface lubricating layer after repeated wear, causing the coefficient of friction to continuously increase. Moreover, once the precipitated silicone oil is lost, it cannot be recovered through subsequent heat treatment. Third, the dynamic crosslinking technology of borate esters, exemplified by Oak Ridge National Laboratory (ORNL) in the United States, uses phenylboronic acid ester-based SEBS and small molecule polyols (such as diglycerides) to construct a reversible covalent network, achieving repeated processing and self-healing of materials. However, the small molecule polyols only act as rigid crosslinking nodes, and their short-chain structure cannot provide lubrication. The material's friction coefficient remains high, making it unsuitable for applications requiring low-friction surfaces. Furthermore, this system does not solve the problem of migration and aggregation of nanofillers during repeated processing. In addition, although silicone rubber systems can achieve anchoring lubrication through reactive fluorosilicone oils, silicone rubber itself is a permanent thermosetting material and lacks thermoplastic recyclability. The surface modification scheme using trifluoropropyl fluorosilicone oil suffers from a far less effective surface lubrication than expected because the surface energy of fluorosilicone oil is actually higher than that of polydimethylsiloxane. Moreover, free boric acid groups are prone to dehydration during high-temperature melting processing, forming borooxanes, leading to functional group loss and metric loss.

[0004] In summary, existing technologies have not solved the problems of interfacial anchoring of nano-reinforced fillers during dynamic processing and the processing stability of boric acid groups at high temperatures. Therefore, it is essential to propose a new high-resilience, self-lubricating TPE material. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a high resilience, self-lubricating TPE material, its preparation method and its uses.

[0006] The first aspect of this invention is to provide a method for preparing a high-resilience, self-lubricating TPE material, comprising the following steps: S1: Hydrogenated styrene-butadiene block copolymer and styrene-ethylene-propylene-styrene block copolymer are mixed and swollen with naphthenic oil to obtain a swollen matrix; S2: The swollen matrix, maleic anhydride, styrene, initiator and antioxidant are fed into an extruder and extruded to obtain maleic anhydride-grafted SEBS; S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylborate are fed into an extruder for reaction, and aminopropyl mono-terminated polydimethylsiloxane is added. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. S4: Neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano silica and anti-hydrolysis agent are put into an extruder, vacuum devolatilization extrusion, followed by cooling, shaping and pelletizing to obtain a high-resilience, self-lubricating TPE material.

[0007] It should be noted that the present invention obtains neopentyl glycol ester of 3-aminophenylboronic acid (3-APBA-Bnpg) by pre-cyclizing 3-aminophenylboronic acid with neopentyl glycol. The 1,3-dihydroxyl group of neopentyl glycol dehydrates with the two hydroxyl groups of boric acid to form a cyclic borate ester. The boron center is in a stable state and does not dehydrate or oxidize during melt processing at 180-195℃, and its hydrolysis sensitivity is significantly reduced.

[0008] This invention innovatively utilizes 3-APBA-Bnpg as a dormant boron source (the borate group is in a dormant state). In step S3, the amino group at one end of 3-APBA-Bnpg first undergoes an amidation reaction with the anhydride group of maleic anhydride-grafted SEBS (SEBS-g-MAH), grafting the cyclic borate ester onto the SEBS molecular chain (see Chemical Formula 1). Then, aminopropyl-terminated PDMS is added. The amino group of the aminopropyl-terminated PDMS undergoes an amidation reaction with the residual anhydride on SEBS-g-MAH. The PDMS segment is connected to the SEBS main chain through an imide bond, forming a side chain cantilever, to obtain neopentyl glycol borate ester-silicone co-grafted SEBS (see Chemical Formula 2).

[0009] SEBS-g-MAH+H2N–Ar–B(Bnpg)→SEBS-g-[Im–Ar–B(Bnpg)]+H2O↑ (Equation 1) P(–g-Im–Ar–B(Bnpg))+H2N–(CH2)3–PDMS→ P(–g-Im–Ar–B(Bnpg))(–g-Im–(CH2)3–PDMS)+ H2O↑ (Equation 2) Wherein, P is the SEBS backbone; Ar is 3-aminophenyl; Bnpg is neopentyl glycol borate ester; Im is an imide group; and -g- is a graft connection.

[0010] In step S4 melt extrusion, the terminal hydroxyl groups of the hydroxypropyl PDMS attack the boron center of the cyclic borate ester, resulting in ring-opening transesterification. Neopentyl glycol is removed as a byproduct, shifting the equilibrium to the right. The borate group is activated and forms a borate ester crosslinking node with polydimethylsiloxane (PDMS) diol. The polysiloxane segment simultaneously acts as a crosslinking bridge and a bulk lubricant, forming a borate ester network (see Chemical Formula 3). At the same time, the single-terminal hydroxyl perfluoropolyether participates in transesterification at one end, while the other end is capped with a perfluoroalkyl group to remain free, forming a pendant chain that can migrate to the surface, constructing a fluorine-silica gradient lubricating layer (see Chemical Formula 4). The residual anhydride and amino-modified nano-silica are amidated to achieve chemical anchoring of the filler. The free radical reaction is concentrated in step S1. Steps S2-S4 no longer introduce peroxides and Lewis bases, avoiding high-temperature oxidation side reactions of the borate ester groups, and finally obtaining a thermoplastic elastomer with high resilience, long-lasting self-lubrication, wear self-repair, and reprocessability.

[0011] nP-B+nHO-(CH2)3-PDMS-(CH2)3-OH→ [PB(O-(CH2)3-PDMS-(CH2)3-O-)2] n (3D network) + n NPG↑ (Equation 3) P-B+HO-PFPE-R f +HO-(CH2)3-PDMS-(CH2)3-OH→ PB(O-PFPE-R f )(O-(CH2)3-PDMS-(CH2)3-OH) + NPG↑ (Equation 4) Among them, the co-grafted SEBS is PB (P main chain simultaneously connected to dormant borate ester site -Im-Ar-B(Bnpg) and silicone cantilever -Im-(CH2)3-PDMS); R f It is a perfluoroalkyl / perfluoroether end-capped group; NPG is neopentyl glycol (2,2-dimethyl-1,3-propanediol).

[0012] In some embodiments, the mass ratio of hydrogenated styrene-butadiene block copolymer, styrene-ethylene-propylene-styrene block copolymer, and naphthenic oil is 5.5-6.5:3.8-4.2:4.7-5.2; the viscosity of the naphthenic oil at 40°C is 145-165 mmHg. 2 / s.

[0013] In some embodiments, the mass ratio of maleic anhydride, styrene, initiator and antioxidant is 1.5-2.5:1.8-2.2:0.2-0.4:0.3-0.5; the mass ratio of swollen matrix and maleic anhydride is 14.8-15.2:0.18-0.22.

[0014] In some embodiments, the initiator is selected from at least one of dicumyl peroxide and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0015] In some embodiments, the mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylborate, and aminopropyl mono-terminated polydimethylsiloxane is 150-155:1-1.4:4-7; the mass ratio of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, mono-hydroxyl-terminated perfluoropolyether, amino-modified nano-silica, and anti-hydrolysis agent is 160-165:7-8:1-1.5:6-9:0.2-0.5; and the anti-hydrolysis agent is polycarbodiimide.

[0016] The amino-modified nano-silica is prepared by the following steps: 100 parts by weight of nano-silica were added to 1500 parts by weight of anhydrous ethanol, ultrasonically dispersed, and then deionized water was added to adjust the pH to 4-5. The mixture was pre-acidified and dispersed by stirring in a 60°C water bath for 30 min. 8 parts by weight of KH-550 (γ-aminopropyltriethoxysilane) were added dropwise, and the mixture was refluxed at 60-70°C for 6 h for hydrolysis and condensation. Then, it was centrifuged at 4000 r / min for 10 min, washed three times with anhydrous ethanol, vacuum dried at 60°C for 12 h, and ground through a 200-mesh sieve to obtain the final product. Those skilled in the art can also prepare amino-modified nano-silica by other means; this method is not limited to these methods.

[0017] In some embodiments, the extruder temperature in S2 is 165-185°C; the extruder temperature in S3 is 180-195°C; and the extruder temperature in S4 is 175-190°C.

[0018] In some embodiments, neopentyl glycol 3-aminophenylboronic acid is prepared by the following steps: 3-Aminophenylboronic acid and neopentyl glycol were added to a solvent and refluxed. The mixture was then distilled under reduced pressure and dried to obtain neopentyl glycol ester of 3-aminophenylboronic acid.

[0019] In some embodiments, the molar ratio of 3-aminophenylboronic acid to neopentyl glycol is 1:1.03-1.07; the mass of the solvent used is 5-10 times the sum of the masses of 3-aminophenylboronic acid and neopentyl glycol; the solvent is selected from anhydrous toluene and xylene.

[0020] The second aspect of this invention is to provide a method for preparing a high-resilience, self-lubricating TPE material, thereby obtaining a high-resilience, self-lubricating TPE material.

[0021] A third aspect of this invention is to provide an application of a high-resilience, self-lubricating TPE material in the field of sealing components.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects: 1. This invention uses neopentyl glycol 3-aminophenylboronic acid (3-APBA-Bnpg) as a dormant boron source that is stable during melt processing. This compound pre-cyclizes the borate group into a neopentyl glycol ester protective structure, ensuring the stability of the boron center during melt extrusion at 180-195°C. This avoids the uncontrollable morphology of boron species caused by the dehydration of free arylboronic acid to borooxanes at high temperatures, allowing for precise stoichiometric control of the amount of boron ester crosslinking sites introduced. Neopentyl glycol ester lies between pinacol esters (which have insufficient exchange kinetics) and open-chain, easily hydrolyzed methyl esters, balancing processing tolerance and reaction feasibility. Its cyclic protecting group has less steric hindrance than pinacol esters, and the terminal hydroxypropyl PDMS can attack the boron center to undergo ring-opening transesterification. The byproduct neopentyl glycol is effectively removed under vacuum, shifting the equilibrium to the right. The amino group at one end of the monomer is amidated with the anhydride group of SEBS-g-MAH, grafting the cyclic borate ester onto the molecular chain. The neopentyl glycol ring at the other end is not activated until step S4. This sequential design of grafting followed by activation keeps the borate ester bond dormant and prevents exchange, avoiding premature gelation of the melt at the grafting section and ensuring processability. Furthermore, in step S3, the aromatic amine (3-APBA-Bnpg) and the fatty amine (aminopropyl PDMS) are fed in steps to avoid competitive reactions between the two amines and the anhydride, ensuring controllable crosslinking density and batch consistency. No peroxides or Lewis bases enter the later stages of the process, protecting the borate ester groups from oxidation, ultimately yielding a thermoplastic elastomer with high resilience, long-lasting self-lubrication, wear self-repair, and reprocessability.

[0023] 2. The thermoplastic elastomer provided by this invention possesses excellent lubricity, resilience, and hydrolysis resistance. The material surface exhibits stable and long-lasting lubrication performance, a low coefficient of friction, and amino-functionalized silica chemically anchored in the matrix through an amidation reaction. During repeated processing, the filler does not migrate or agglomerate. The material maintains stable mechanical properties under long-term thermal cycling and mechanical loads, and its interfacial shear strength is significantly improved compared to physically blended systems. After aging by immersion in hot water, the elastomer shows a low rate of mass change and retains its structural integrity, making it suitable for humid environments, underwater equipment, and medical devices requiring repeated steam sterilization. The material as a whole combines high elasticity, low friction, recyclability, and hydrolysis resistance, making it valuable for applications in automotive sealing, precision transmission, food machinery, and medical devices. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments.

[0025] Example 1 A high-resilience, self-lubricating TPE material is prepared by the following steps: S1: Hydrogenated styrene-butadiene block copolymer (SEBS) and styrene-ethylene-propylene-styrene block copolymer (SEPS) were mixed, and naphthenic oil (KN4010 naphthenic rubber oil, Shenzhen Huashengyuan Petroleum Technology Co., Ltd.) was added to swell the mixture. The mixture was stirred at 900 r / min for 10 min at 70℃, sealed and allowed to stand for 12 h to swell, thus obtaining the swollen matrix. The mass ratio of hydrogenated styrene-butadiene block copolymer, styrene-ethylene-propylene-styrene block copolymer and naphthenic oil was 6:4:5. S2: The swollen matrix is ​​premixed with maleic anhydride, styrene, dicumyl peroxide and antioxidant in a mass ratio of 2:2:0.3:0.4 at room temperature and low speed for 5 min. The mixture is then fed into an extruder at 170℃ for in-situ grafting to obtain maleic anhydride-grafted SEBS. The mass ratio of the swollen matrix to maleic anhydride is 15:0.2, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are placed in an extruder at 190°C and reacted for 1-2 minutes. Then, aminopropyl mono-terminated polydimethylsiloxane is added and reacted for another 1-2 minutes. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylboronic acid, and aminopropyl mono-terminated polydimethylsiloxane is 153:1.2:5. S4: A mixture of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano-silica, and polycarbodiimide in a mass ratio of 162:7.5:1.2:7:0.3 is placed in an extruder at a temperature of 185°C. Neopentyl glycol is removed under vacuum. After extrusion, the mixture is cooled, shaped, and pelletized to obtain a high-resilience, self-lubricating TPE material.

[0026] The amino-modified nano-silica is prepared by the following steps: 100 parts by weight of nano-silica were added to 1500 parts by weight of anhydrous ethanol, ultrasonically dispersed, and then deionized water was added to adjust the pH to 4-5. The mixture was pre-acidified and dispersed by stirring in a water bath at 60°C for 30 min. 8 parts by weight of KH-550 (γ-aminopropyltriethoxysilane) were added dropwise, and the mixture was refluxed at 65°C for 6 h to hydrolyze and condense. Then, it was centrifuged at 4000 r / min for 10 min, washed three times with anhydrous ethanol, vacuum dried at 60°C for 12 h, and ground through a 200-mesh sieve to obtain the final product.

[0027] Neopentyl glycol 3-aminophenylboronic acid was prepared by the following steps: 3-Aminophenylboronic acid and neopentyl glycol in a molar ratio of 1:1.05 were added to anhydrous toluene and refluxed at 120°C for 3.5 h. The water generated during esterification was removed by azeotropic distillation, the solvent was removed by vacuum distillation, and the product was dried under vacuum at 60°C for 4 h to obtain neopentyl glycol ester of 3-aminophenylboronic acid. The mass of anhydrous toluene used was 8 times the sum of the masses of 3-aminophenylboronic acid and neopentyl glycol.

[0028] FTIR (ATR) analysis showed that the TPE material in this embodiment was at 1780 cm⁻¹ -1 With 1860 cm -1 The C=O stretching vibration peak of the acid anhydride was significantly weakened at 1770 cm⁻¹. -1 With 1700 cm -1 The characteristic absorption of imide C=O appears at 1080 cm⁻¹. -1 With 1020 cm -1 A strong Si-O-Si absorption peak appears at 1260 cm⁻¹. -1 The characteristic peak of Si-CH3 appears at 1342 cm⁻¹, and at 1342 cm⁻¹... -1 BO bond characteristic absorption was detected; acid-base titration determined that the MAH content grafted onto the TPE material was 1.0 wt%. 11 B NMR (toluene-d8 swollen HR-MAS) shows a tricoordinate sp2 group at δ ~ +30 ppm. 2 The broadened signal of borate esters showed that no tetracoordinated borate signal was detected in the δ0~+10ppm range; 1H NMR detected the Si-CH3 signal of PDMS at δ~0.1ppm, consistent with the presence of silicon in the system; XPS showed that the surface F / C atomic ratio was about 0.27, and the B1s signal was weak and close to the detection limit.

[0029] Example 2 A high-resilience, self-lubricating TPE material is prepared by the following steps: S1: Mix SEBS and SEPS, add naphthenic oil (KN4010 naphthenic rubber oil, Shenzhen Huashengyuan Petroleum Technology Co., Ltd.) to swell, stir at 800 r / min for 10 min at 80℃, seal and let stand for 12 h to swell, and obtain the swollen matrix; wherein, the mass ratio of SEBS, SEPS and naphthenic oil is 6.5:4.2:5.2; S2: The swollen matrix is ​​premixed with maleic anhydride, styrene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and antioxidant in a mass ratio of 2.5:2.2:0.4:0.5 at room temperature and low speed for 5 min. The mixture is then in-situ grafted in an extruder at 185℃ to obtain maleic anhydride-grafted SEBS. The mass ratio of the swollen matrix to maleic anhydride is 15.2:0.22, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are placed in an extruder at 195°C and reacted for 1-2 minutes. Then, aminopropyl mono-terminated polydimethylsiloxane is added and reacted for another 1-2 minutes. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylboronic acid, and aminopropyl mono-terminated polydimethylsiloxane is 155:1.4:7. S4: A mixture of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano-silica, and polycarbodiimide in a mass ratio of 165:8:1.5:9:0.5 is fed into an extruder at a temperature of 190°C. Neopentyl glycol is removed under vacuum. After extrusion, the mixture is cooled, shaped, and pelletized to obtain a high-resilience, self-lubricating TPE material.

[0030] The amino-modified nano-silica in this embodiment is the same as that in Example 1.

[0031] Neopentyl glycol 3-aminophenylboronic acid was prepared by the following steps: 3-Aminophenylboronic acid and neopentyl glycol in a molar ratio of 1:1.07 were added to xylene and refluxed at 130°C for 3 h. The water generated during esterification was removed by azeotropic distillation, the solvent was removed by vacuum distillation, and the product was dried under vacuum at 60°C for 4 h to obtain neopentyl glycol ester of 3-aminophenylboronic acid. The mass of xylene used was 10 times the sum of the masses of 3-aminophenylboronic acid and neopentyl glycol.

[0032] FTIR shows the imide C=O peak (1770 / 1700 cm⁻¹) of the TPE material in this embodiment. -1 The strength is higher than that of Example 1, 1345 cm. -1 The BO peak was also stronger, and the residual anhydride peak almost completely disappeared; the content of grafted MAH was 1.15 wt% as determined by acid-base titration, which was the highest among the five cases; 11 B NMR shows tricoordinate sp at δ ~ +30 ppm. 2 The broadened signal of boronic ester with a relatively large peak area is consistent with the high feed amount of 3-APBA-Bnpg. 1 H NMR detected a Si-CH3 signal in PDMS (δ ~0.1 ppm); XPS showed that the surface F / C atomic ratio was approximately 0.34, which is consistent with the maximum amount of PFPE monool fed, and B1s was close to the detection limit.

[0033] Example 3 A high-resilience, self-lubricating TPE material is prepared by the following steps: S1: Mix SEBS and SEPS, add naphthenic oil (KN4010 naphthenic rubber oil, Shenzhen Huashengyuan Petroleum Technology Co., Ltd.) to swell, stir at 1000 r / min for 10 min at 60℃, seal and let stand for 12 h to swell, and obtain the swollen matrix; wherein, the mass ratio of SEBS, SEPS and naphthenic oil is 5.5:3.8:4.7; S2: The swollen matrix is ​​premixed with maleic anhydride, styrene, dicumyl peroxide and antioxidant in a mass ratio of 1.5:1.8:0.2:0.3 at room temperature and low speed for 5 min. The mixture is then fed into an extruder at 165℃ for in-situ grafting to obtain maleic anhydride-grafted SEBS. The mass ratio of the swollen matrix to maleic anhydride is 14.8:0.18, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are placed in an extruder at 180°C and reacted for 1-2 minutes. Then, aminopropyl mono-terminated polydimethylsiloxane is added and reacted for another 1-2 minutes. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylboronic acid, and aminopropyl mono-terminated polydimethylsiloxane is 150:1:4. S4: A mixture of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano silica, and polycarbodiimide in a mass ratio of 160:7:1:6:0.2 is fed into an extruder at a temperature of 175°C. Neopentyl glycol is removed under vacuum. After extrusion, the mixture is cooled, shaped, and pelletized to obtain a high-resilience, self-lubricating TPE material.

[0034] The amino-modified nano-silica in this embodiment is the same as that in Example 1.

[0035] Neopentyl glycol 3-aminophenylboronic acid was prepared by the following steps: 3-Aminophenylboronic acid and neopentyl glycol in a molar ratio of 1:1.03 were added to anhydrous toluene and refluxed at 110°C for 4 h. The water generated during esterification was removed by azeotropic distillation, the solvent was removed by vacuum distillation, and the product was dried under vacuum at 60°C for 4 h to obtain neopentyl glycol ester of 3-aminophenylboronic acid. The mass of anhydrous toluene used was 5 times the sum of the masses of 3-aminophenylboronic acid and neopentyl glycol.

[0036] FTIR shows the imide C=O peak (1770 / 1700 cm⁻¹) of the TPE material in this embodiment. -1 ) and BO peak (1340 cm) -1 All of them were identifiable but the intensity was relatively weak, and the residual anhydride signal was slightly higher than that of other examples; the content of grafted MAH was 0.75 wt% as determined by acid-base titration, which was related to the low amount of MAH and DCP and the low grafting temperature (165°C); 11 Tricoordinated sp was detected by B NMR at δ ~ +30 ppm. 2 The boronic ester broadened signal had a relatively small peak area, consistent with the minimum amount of 3-APBA-Bnpg feed, and no tetracoordinated boron signal was detected. 1 H NMR detected the Si-CH3 signal of PDMS at δ~0.1ppm, with the weakest signal; the B1s signal on the XPS surface was weak and close to the detection limit, with an F / C atomic ratio of about 0.21.

[0037] Example 4 A high-resilience, self-lubricating TPE material is prepared by the following steps: S1: Mix SEBS and SEPS, add naphthenic oil (KN4010 naphthenic rubber oil, Shenzhen Huashengyuan Petroleum Technology Co., Ltd.) to swell, stir at 1000 r / min for 10 min at 75℃, seal and let stand for 12 h to swell, and obtain the swollen matrix; wherein, the mass ratio of SEBS, SEPS and naphthenic oil is 5.8:3.9:4.9; S2: The swollen matrix is ​​premixed with maleic anhydride, styrene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and antioxidant in a mass ratio of 1.8:1.9:0.25:0.35 at room temperature and low speed for 5 min. The mixture is then in-situ grafted in an extruder at 175℃ to obtain maleic anhydride-grafted SEBS. The mass ratio of the swollen matrix to maleic anhydride is 14.9:0.19, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are placed in an extruder at 190°C and reacted for 1-2 minutes. Then, aminopropyl mono-terminated polydimethylsiloxane is added and reacted for another 1-2 minutes. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylboronic acid, and aminopropyl mono-terminated polydimethylsiloxane is 152:1.1:5. S4: A mixture of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano-silica, and polycarbodiimide in a mass ratio of 162:7.2:1.2:7:0.3 is fed into an extruder at a temperature of 185°C. Neopentyl glycol is removed under vacuum. After extrusion, the mixture is cooled, shaped, and pelletized to obtain a high-resilience, self-lubricating TPE material.

[0038] In this embodiment, the amino-modified nano-silica and neopentyl glycol 3-aminophenylboronic acid are the same as those in Example 1.

[0039] The FTIR spectrum in this embodiment is similar to that in Example 1, 1770 / 1700 cm⁻¹ -1 imide peak and 1343 cm -1 The BO peak was clear, while the residual anhydride peak was weak; acid-base titration determined the grafted MAH content to be 0.88 wt%. 11 B NMR shows tricoordinate sp at δ ~ +30 ppm. 2 Boronate broadening signal; 1 H NMR detected the Si-CH3 signal of PDMS at δ~0.1ppm; XPS showed that the surface F / C atomic ratio was about 0.27, which is the same as the amount of PFPE monool fed and in Example 1, and the B1s signal was weak and close to the detection limit.

[0040] Example 5 A high-resilience, self-lubricating TPE material is prepared by the following steps: S1: Mix SEBS and SEPS, add naphthenic oil (KN4010 naphthenic rubber oil, Shenzhen Huashengyuan Petroleum Technology Co., Ltd.) to swell, stir at 950 r / min for 10 min at 80℃, seal and let stand for 12 h to swell, and obtain the swollen matrix; wherein, the mass ratio of SEBS, SEPS and naphthenic oil is 6.3:4.1:5.1; S2: The swollen matrix is ​​premixed with maleic anhydride, styrene, dicumyl peroxide and antioxidant in a mass ratio of 2.3:2.1:0.35:0.45 at room temperature and low speed for 5 min. The mixture is then fed into an extruder at 180℃ for in-situ grafting to obtain maleic anhydride-grafted SEBS. The mass ratio of the swollen matrix to maleic anhydride is 15.1:0.21. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1. S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are placed in an extruder at 190°C and reacted for 1-2 minutes. Then, aminopropyl mono-terminated polydimethylsiloxane is added and reacted for another 1-2 minutes. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylboronic acid, and aminopropyl mono-terminated polydimethylsiloxane is 154:1.3:6. S4: A mixture of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano silica, and polycarbodiimide in a mass ratio of 164:7.8:1.4:8:0.4 is placed in an extruder at a temperature of 185°C. Neopentyl glycol is removed under vacuum. After extrusion, the mixture is cooled, shaped, and pelletized to obtain a high-resilience, self-lubricating TPE material.

[0041] In this embodiment, the amino-modified nano-silica and neopentyl glycol 3-aminophenylboronic acid are the same as those in Example 1.

[0042] The FTIR in this embodiment shows an imide peak (1770 / 1700 cm⁻¹). -1 ) and BO peak (1344 cm) -1 The strength was high, consistent with the high total content of 3-APBA-Bnpg and PDMS; the content of grafted MAH determined by acid-base titration was 1.05 wt%. 11 B NMR shows tricoordinate sp from δ to +30 ppm. 2 Boronate broadening signal; 1 The Si-CH3 signal (δ~0.1ppm) of PDMS can be clearly detected in H NMR; the F / C atomic ratio on the XPS surface is about 0.31, which is higher than that in Example 1 but lower than that in Example 2, which is consistent with the high amount of PFPE monool fed; the B1s signal is weak and close to the detection limit.

[0043] Comparative Example 1 The process is basically the same as in Example 1, except that S3 does not include neopentyl glycol 3-aminophenylborate and aminopropyl mono-terminated polydimethylsiloxane. S3 is as follows: maleic anhydride-grafted SEBS, dicumyl peroxide and crosslinking agent TAIC in a mass ratio of 153:0.4:2 are put into an extruder at a temperature of 190°C and reacted for 1-2 minutes to obtain permanently crosslinked peroxide crosslinked SEBS. S4 is not required.

[0044] Comparative Example 2 It is basically the same as Example 1, except that the hydroxypropyl-terminated polydimethylsiloxane and the single-terminated hydroxyl perfluoropolyether in S4 are replaced with diglycerides in equal molar amounts of OH.

[0045] Comparative Example 3 The results are basically the same as in Example 1, except that: no aminopropyl mono-terminated polydimethylsiloxane is added in S3, and free methyl silicone oil of the same mass as aminopropyl mono-terminated polydimethylsiloxane is added in S4.

[0046] Comparative Example 4 This is basically the same as Example 1, except that the single-ended hydroxyl perfluoropolyether in S4 is replaced with an equal molar amount of double-ended OH-PFPE.

[0047] Comparative Example 5 It is basically the same as Example 1, except that neopentyl glycol 3-aminophenylboronic acid is replaced with an equal molar amount of 3-aminophenylboronic acid.

[0048] Comparative Example 6 It is basically the same as Example 1, except that in S3, neopentyl glycol 3-aminophenylboronic acid and aminopropyl mono-terminated polydimethylsiloxane are added at the same time.

[0049] Comparative Example 7 It is basically the same as Example 1, except that the amino-modified nano silica is replaced with the same mass of unmodified silica.

[0050] Comparative Example 8 It is basically the same as Example 1, except that in S4, 2-ethyl-4-methylimidazole (Lewis base) is added, and the mass amount is 0.12% of the mass of neopentyl glycol borate-silicone co-grafted SEBS.

[0051] The thermoplastic elastomers prepared in Examples 1-5 and Comparative Examples 1-8 were subjected to performance tests, and the test results are shown in Tables 1 and 2.

[0052] Tensile strength and elongation at break tests: Refer to standard GB / T 1040.2, use type I dumbbell-shaped specimens, thickness 2.0±0.2mm, tensile rate 50mm / min, 23±2℃; Compression set test: Refer to standard GB / T 7759.1, use type A specimen (diameter 29.0±0.5mm, height 12.5±0.5mm), compression rate 25%, 70℃×24h, and measure 30min after unloading; Rebound rate test: Refer to standard GB / T 1681, use the falling ball method, steel ball diameter 16.0mm, mass 35.0g, drop height 500mm, rebound height to drop height ratio; Friction coefficient μ test: The ball-disc reciprocating friction test method was adopted, using GCr15 steel ball (φ6mm), load 2N, frequency 2Hz, amplitude 5mm, dry friction at room temperature, and steady state value was obtained after running for 10min; Friction coefficient (after 1000 wear cycles) test: After 1000 reciprocating wear cycles, the friction coefficient is tested in situ, using the same method as above; Friction coefficient recovery rate: After wear, heat treatment at 175℃ for 30 min is performed, and the friction coefficient is tested again. The result is calculated as (after wear - after recovery) / (after wear - initial) × 100%. The test method is the same as above. Hydrolysis resistance: The elastomer was immersed in deionized water at 80℃ for 72 hours, then removed and dried. The mass change rate was calculated as (m_after - m_before) / m_before × 100%. Gel retention rate test: The toluene reflux extraction method was used. The elastomer was soaked in deionized water at 80℃ for 72h, dried under vacuum at 60℃ to constant weight, and m1 was accurately weighed. After toluene reflux extraction for 48h, the insoluble matter was removed, dried under vacuum at 60℃ to constant weight, and m2 was weighed. The gel rate = m2 / m1×100%. The gel retention rate was calculated by comparing it with the gel rate of the unsoaked control sample. Water contact angle test: The contact angle was measured using the seated drop method with a 2μL drop of deionized water at room temperature and image analysis. The average of 5 measurements was taken.

[0053] Table 1 Test data for Examples 1-5

[0054] Table 2 Test data for comparative examples 1-8

[0055] As shown in Table 1, the TPE materials prepared in Examples 1-5 of this invention exhibit high self-lubrication, high resilience, and self-healing properties. The thermoplastic elastomers provided in these examples achieve reproducible processing of the dynamic network within a reasonable range of 25-31% compression set and 70-80% resilience. Simultaneously, fluorine / silicone segments migrate to the surface via borate ester bond exchange. Under heat treatment at 175℃ for 30 min, the friction coefficient recovery rate can reach over 85%, and after immersion in 80℃ hot water for 72 h, the gelation rate retention rate is ≥90%, and the mass change rate is <0.5%, verifying the structural integrity of the elastomer. All data are significantly better than those of the comparative examples.

[0056] As shown in Table 2, Comparative Example 1, using DCP / TAIC permanent crosslinking, exhibited a 14% compression set and 86% springback, superior to the Example. However, due to the irreversible crosslinking, the material could not be melted and reprocessed, rendering the friction recovery rate test meaningless (denoted as N / A), demonstrating that the reprocessability of the dynamic network is irreplaceable. Comparative Example 2, using diglycerol instead of polysiloxane diol, achieved a similar gelation rate but a higher coefficient of friction of 0.45, which increased to 0.48 after wear. This is because the small molecule polyol lacks lubricating segments, resulting in poor friction recovery. Recovery rate was not tested; Comparative Example 3 used free methyl silicone oil instead of grafted silicone, and the initial friction coefficient of 0.11 was close to that of the example, but it rose to 0.22 after 1000 wear cycles, with a recovery rate of only 45%. Furthermore, after 30 days of storage, the water contact angle recovered from 95° to 108°, demonstrating the necessity of covalent anchoring for long-term lubrication; Comparative Example 4 used double-ended OH-PFPE instead of single-ended OH-PFPE, and the friction coefficient of 0.18 and recovery rate of 55% were both inferior to the example, because the double-ended bridging locked the PFPE in the network, losing its surface adhesion. Migration ability; Comparative Example 5 replaced the dormant boron source 3-APBA-Bnpg with free 3-APBA, with a gel rate of <15%, tensile strength of 3.2 MPa, compression set >60% and rebound rate of <30%. The material had become a melt and lacked elasticity, and many tests were meaningless; Comparative Example 6 replaced the stepwise amidation with simultaneous feeding, with a gel rate of 42%, tensile strength of 7.5 MPa, and compression set of 35%. Due to the competitive consumption of acid anhydrides by aliphatic amines, there were insufficient Bnpg sites, and the crosslinking density decreased; Comparative Example 7 replaced the amino-functionalized type with unmodified SiO2. The initial performance was similar to the examples, but the migration and aggregation of SiO2 during processing led to the decay of mechanical properties, and the gel rate retention rate also decreased significantly, proving the necessity of chemical anchoring for the stability of the filler interface; Comparative Example 8 added an imidazole Lewis base, with a compression set of 42% and a rebound rate of 58%. Due to the accelerated borate ester exchange catalyzed by the base, the network continued to relax and creep at the service temperature, and the gel rate retention rate was only 85% after 72 hours in water at 80°C.

[0057] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-resilience, self-lubricating TPE material, characterized in that, Includes the following steps: S1: Hydrogenated styrene-butadiene block copolymer and styrene-ethylene-propylene-styrene block copolymer are mixed and swollen with naphthenic oil to obtain a swollen matrix; S2: The swollen matrix, maleic anhydride, styrene, initiator and antioxidant are fed into an extruder and extruded to obtain maleic anhydride-grafted SEBS; S3: Maleic anhydride-grafted SEBS and neopentyl glycol 3-aminophenylboronic acid are fed into an extruder for reaction, and aminopropyl mono-terminated polydimethylsiloxane is added. The mixture is then extruded to obtain neopentyl glycol borate-silicone co-grafted SEBS. S4: The neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, single-hydroxyl-terminated perfluoropolyether, amino-modified nano silica and anti-hydrolysis agent are put into an extruder, vacuum devolatilization extrusion, followed by cooling, shaping and pelletizing to obtain the high resilience and self-lubricating TPE material.

2. The method for preparing the high-resilience, self-lubricating TPE material according to claim 1, characterized in that, The mass ratio of the hydrogenated styrene-butadiene block copolymer, the styrene-ethylene-propylene-styrene block copolymer, and the naphthenic oil is 5.5-6.5:3.8-4.2:4.7-5.2; the naphthenic oil has a viscosity of 145-165 mmHg at 40°C. 2 / s.

3. The method for preparing the high-resilience, self-lubricating TPE material according to claim 1, characterized in that, The mass ratio of maleic anhydride, styrene, initiator and antioxidant is 1.5-2.5:1.8-2.2:0.2-0.4:0.3-0.5; the mass ratio of swollen matrix and maleic anhydride is 14.8-15.2:0.18-0.

22.

4. The method for preparing the high-resilience, self-lubricating TPE material according to claim 3, characterized in that, The initiator is selected from at least one of dicumyl peroxide and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

5. The method for preparing the high-resilience, self-lubricating TPE material according to claim 1, characterized in that, The mass ratio of maleic anhydride-grafted SEBS, neopentyl glycol 3-aminophenylborate, and aminopropyl mono-terminated polydimethylsiloxane is 150-155:1-1.4:4-7; the mass ratio of neopentyl glycol borate-silicone co-grafted SEBS, hydroxypropyl-terminated polydimethylsiloxane, mono-hydroxyl-terminated perfluoropolyether, amino-modified nano-silica, and anti-hydrolysis agent is 160-165:7-8:1-1.5:6-9:0.2-0.5; the anti-hydrolysis agent is polycarbodiimide.

6. The method for preparing the high-resilience, self-lubricating TPE material according to claim 1, characterized in that, The extruder temperature in S2 is 165-185℃; the extruder temperature in S3 is 180-195℃; and the extruder temperature in S4 is 175-190℃.

7. The method for preparing the high-resilience, self-lubricating TPE material according to claim 1, characterized in that, The neopentyl glycol ester of 3-aminophenylboronic acid was prepared by the following steps: 3-Aminophenylboronic acid and neopentyl glycol are added to a solvent and refluxed. The mixture is then distilled under reduced pressure and dried to obtain the neopentyl glycol ester of 3-aminophenylboronic acid.

8. The method for preparing the high-resilience, self-lubricating TPE material according to claim 7, characterized in that, The molar ratio of 3-aminophenylboronic acid to neopentyl glycol is 1:1.03-1.07; the mass of the solvent used is 5-10 times the sum of the masses of 3-aminophenylboronic acid and neopentyl glycol; the solvent is selected from anhydrous toluene and xylene.

9. A high-resilience, self-lubricating TPE material prepared by the preparation method of any one of claims 1-8.

10. The application of the high resilience, self-lubricating TPE material as described in claim 9 in the field of sealing components.

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