Silicone oil modified lubricant as well as preparation method and application thereof

Abstract

The invention provides a silicone oil modified lubricant as well as a preparation method and application thereof, and belongs to the technical field of silicone oil modified lubricants. The preparation method of the silicone oil modified lubricant comprises the following steps: (1) dissolving hyaluronic acid in water to prepare a hyaluronic acid solution, then mixing the hyaluronic acid solution with a magnesium hydroxide solution, uniformly stirring, and placing the mixed solution in an ice bath condition; (2) dissolving dodecanoyl chloride or octadecanoyl chloride in 1, 4-dioxane, and dropwise adding into the mixture obtained in the step (1) for reaction; and (3) after the reaction is finished, concentrating the product obtained in the step (2), precipitating with ethanol, washing the obtained precipitate, dissolving with deionized water, and freeze-drying to obtain the product. After being mixed with silicone oil, the silicone oil modified lubricant disclosed by the invention can spontaneously form balls and play a role in rolling lubrication, so that friction is greatly reduced, and the silicone oil modified lubricant is simple in preparation method, convenient in process operation, low in preparation cost, wide in application range and capable of maintaining the lubricating performance between interfaces for a long time.

Description

Technical Field

[0001] This invention belongs to the field of advanced materials technology, specifically the field of surface lubrication materials technology, and relates to a silicone oil modified lubricant, its preparation method and application. Background Technology

[0002] Good surface lubrication is of great importance for maintaining the daily activities of organisms and the normal operation of mechanical equipment. Mechanical equipment requires additional lubrication on the surfaces of its contacting parts to ensure long-term normal operation; similarly, related tissues and organs in organisms, such as body cavities, eyeballs, and joints, also require appropriate biological lubrication to maintain normal life activities.

[0003] Lubrication is closely related to friction, and the main purpose of lubrication is to reduce friction. Friction is a natural phenomenon that is ubiquitous in mechanical motion and life activities, such as mechanical operation and joint movement. Although friction is essential for mechanical motion and life activities, excessive friction can also have adverse effects, such as causing heat generation in operating machinery, causing wear and tear on parts, reducing machine precision and shortening service life; or causing sensory discomfort in organisms, inducing inflammation, causing damage to tissues and organs, and reducing the lifespan of biological materials, etc.

[0004] Generally speaking, friction can be classified into internal friction and external friction according to its source; into static friction and kinetic friction according to the motion state of the friction pair surfaces; into sliding friction and rolling friction according to the motion mode of the friction pair surfaces; and into dry friction, boundary friction, fluid friction, and mixed friction according to the lubrication state of the friction pair surfaces. [1] Since components in mechanical equipment and living organisms that require appropriate friction are often in motion, existing technologies, when developing corresponding lubricants, mainly classify friction based on the motion form of the friction pair surfaces and focus their research on reducing sliding or rolling friction between the corresponding components.

[0005] Currently, techniques for increasing lubrication by providing less sliding friction on the surfaces of friction pairs mainly focus on using lubricating oils, adding surface coatings, or modifying the surface of materials. However, sliding friction has an inherent disadvantage of higher friction compared to rolling friction. [2] This limits the effectiveness of the aforementioned methods in improving lubrication. Furthermore, during sliding, lubricating substances are prone to migration and uneven distribution on the friction pair surfaces, or be absorbed by the friction pair, resulting in poor durability of the lubrication effect. Methods that increase lubrication by providing rolling friction on the friction pair surfaces, such as adding microspheres to lubricating oil, suffer from drawbacks such as complex manufacturing processes, high production costs, and narrow applicability, hindering their widespread use.

[0006] For sliding friction pairs, injecting lubricating oil onto the surface of the friction pair is the simplest way to increase lubrication. This forms an oil film on the surface, reducing frictional resistance, power consumption, and wear, thereby improving the reliability and durability of the friction components. However, the added lubricating oil is prone to deterioration in its long-term lubrication effect and insufficient wear resistance due to impurities or oil loss during friction, requiring frequent replenishment.

[0007] Constructing surface coatings is an important way to improve the lubricity of related parts of biomaterials and medical devices and significantly reduce the coefficient of friction. Hydrophilic surface coatings utilize the hydrophilic groups of hydrophilic polymers to absorb large amounts of water, forming a stable hydrophilic cross-linked coating on the material surface. This can be used to improve the lubricity between device surfaces and tissues (such as artificial joints, intraocular lenses, catheters, endoscopes, etc.), thereby reducing friction and wear between materials and tissues. For example, Liu Xiaofu... [3] A PDA-PSBMA coating was prepared, which exhibits excellent lubrication properties in pure water and biofluids, with a friction coefficient as low as 0.003. Applying this low-friction coating to commercial catheters can significantly improve the surface wettability and lubrication of medical catheters. Another example is Singh A. [4] A biomimetic coating was developed, which uses a polymer-assisted method to non-covalently bind hyaluronic acid (HA) onto the surface of biomaterials and tissues. This biomimetic coating exhibits good lubricity on tissue surfaces, and hyaluronic acid can remain within the joint. (Fan Jun) [5] Coating PVC, PUR, and latex catheters with a PVP coating and immersing them in water for 30 seconds resulted in a 90% decrease in the surface friction coefficient compared to uncoated catheters. The lubrication effect and coating adhesion were also significantly better than paraffin oil coatings. Furthermore, the study found that extending water immersion to 24 hours did not significantly change the friction coefficient of the PVP coating. However, these surface coatings suffer from drawbacks such as easy detachment or displacement during friction, significant wear, and poor long-term lubrication.

[0008] To address the issues of coating peeling, displacement, and wear, researchers have attempted surface modification to achieve appropriate lubricity. For example, Wang Xiaomei et al. [6] Modification of the surface of medical polyurethane catheters was performed by cross-linking and grafting a PVP hydrophilic coating onto the surface of the polyurethane catheter. Results showed that the contact angle between the modified PU film and water decreased from 86.3° to 31.7°, indicating a significant improvement in hydrophilicity, which helps the catheter adapt to the human body's fluid environment. For example, Zhang et al. [7]A polyvinylphosphonic acid (PVPA) polymeric lubricating film was prepared on the surface of Ti6Al4V alloy using a horizontal self-assembly evaporation technique. The PVPA-modified Ti6Al4V exhibited excellent tribological properties when sliding with polytetrafluoroethylene balls in PBS solution, demonstrating ultra-low friction and wear under various conditions, as well as good load-bearing capacity. For example, Deng et al. [8] To achieve a highly efficient lubrication interface on the Ti6Al4V titanium alloy surface, a multilayer polymer coating of polyimide / polyacrylic acid (PEI / PAA) polyelectrolyte was prepared on the Ti6Al4V alloy substrate using a layered assembly technique. The PEI / PAA coating modified the Ti6Al4V surface and exhibited sufficient wettability. The coefficient of friction of the modified Ti6Al4V was 0.059, which was 88% lower than that of bare Ti6Al4V. Although surface modification can reduce friction between materials and solve the problems of easy coating peeling and wear to some extent, surface modification methods have significant limitations on the types of materials and application methods, and the modification methods are relatively complex and costly.

[0009] To address the drawbacks of easy migration and wear of lubricating materials in sliding friction systems, researchers have attempted to adjust the mechanical strength of the lubricating substance to maintain its uniform distribution under external forces. For example, Yasushi Okumura et al. [9] Linear polyethylene glycol (PEG) was end-capped, and then PEG molecules were allowed to pass through α-cyclodextrin rings (α-CD). Crosslinking of the cyclodextrin yielded a hydrogel with a figure-eight sliding crosslinking point structure, termed a topological hydrogel. Mechanical property tests showed a significant improvement in its mechanical strength. Under external force, the topological hydrogel maintained the uniformity of its network structure well, dispersing external stress throughout the gel network through the sliding of crosslinking points along the molecular chains. (Sekiguchi et al.)

[10] A nanoporous anolyte silica nanoparticle monolayer array (SNMAs) with an anolyte silica film fixed on an alumina (AAO) substrate was prepared using silica polymerization and a two-step spin-coating technique. Compared with the AAO substrate without a silica SNMA nanocomposite film, the friction coefficient of the prepared silica-SNMA nanocomposite film on the AAO substrate was significantly reduced by 76% under a dry load of 0.98 N. The results also showed that the friction coefficient was even lower than that of the AAO substrate with MoS2 nanoparticle deposition. For example, Wu et al.

[11] A poly(N-isopropylacrylamide) (PNIPAM) / graphene oxide (GO) composite hydrogel was prepared, in which GO played a significant reinforcing role. Furthermore, by altering external environmental stimuli such as temperature and the proportion of the hydrogel components themselves, the frictional behavior of the hydrogel surface was regulated, resulting in a novel temperature-sensitive smart frictional soft material with certain strength. However, this technology suffers from the problem of excessive swelling of PNIPAM / GO in water, leading to poor mechanical strength. Therefore, while adding graphene oxide to improve the mechanical modulus of the hydrogel material, the sustainability of this improvement is questionable.

[0010] To overcome the inherent high friction of sliding friction pairs, and inspired by the ultra-low friction of human joints, researchers have also conducted biomimetic designs of lubricating materials to achieve better lubrication. For example, Moro...

[12] By grafting the biocompatible phospholipid polymer poly(2-methacryloyloxyethylphosphocholine) (PMPC) onto highly cross-linked polyethylene (CLPE), the hydrophilicity and lubricity of the resulting material are improved through the nanoscale PMPC layer's ability to mimic the hydrogel structure of cartilage; another example is Ma et al.

[13] Based on a soft / hard combination strategy, a novel ordered hydrogel nanoparticle array composite surface was prepared in anodized aluminum oxide (AAO) nanoporous template. The soft hydrogel fibers provide excellent aqueous lubrication, while the hard AAO phase provides high load-bearing capacity. Their synergistic effect indicates that a very low coefficient of friction (<0.01) can be achieved under heavy load conditions (contact pressure ≈2 MPa). Besides hydrogel materials, researchers have also designed polymer brush materials and grafted them onto polymer surfaces to mimic the lubricating function of natural cartilage, thereby improving the frictional properties and wear resistance of polymer materials. For example, Wei Q. et al.

[14] A DLC thin layer was first constructed on the surface of silicon, and then SPMA was reacted via SI-ATRP to finally prepare a polymer brush coating. The resulting PSPMA brush surface exhibited an extremely low and stable coefficient of friction, and its strong adhesion prevented the brush from detaching from the substrate during friction tests. For example, Kobayashi M. et al.

[15] First, an initiator was constructed on a silicon wafer, and then MPC polymerization was initiated to prepare a surface-grafted polymer brush coating. The dense polymer brush prepared on the silicon wafer exhibits superhydrophilicity, with an extremely low coefficient of friction in aqueous media. However, similar biomimetic design schemes, especially the preparation of polymer brushes, typically require cumbersome steps and harsh reaction conditions, limiting the practical application of this technology.

[0011] In summary, existing technologies for increasing lubrication by reducing sliding friction in sliding friction pairs generally suffer from drawbacks such as high coefficient of friction, easy wear, migration, or absorption of lubricating substances during friction, and complex and costly preparation processes for lubricating materials. As a result, the materials obtained either lack long-term lubrication or lack good practical application value.

[0012] Considering that rolling friction typically has lower friction than sliding friction, researchers are actively developing lubricating materials that can provide rolling friction pairs. These lubricating materials are mainly prepared by adding nanospheres. In these materials, the nanospheres can roll freely on the friction pair like bearings, thus acting as micro-bearings to improve load-bearing capacity and reduce the coefficient of friction.

[16] For example, Zhang Li et al.

[17] Oil-soluble nano-titanium oxide particles were prepared using an aluminum-zirconium coupling agent as a modifier via a sol-gel method. When added to heavy-duty vehicle gear oil, the results showed that the nano-titanium oxide particles significantly improved the tribological properties of the lubricating oil. (Nie Qian et al.)

[18] The use of titanium dioxide nanoparticles as a lubricating oil additive was studied. The results showed that adding organically modified titanium dioxide nanoparticles to liquid paraffin improved the paraffin's anti-wear properties and load-bearing capacity, reducing wear scar diameter by 39% and increasing load-bearing capacity by more than double. (Gu Zhuoming et al.)

[19] The synergistic effect of combining nano-calcium carbonate particles and nano-copper particles in improving lubricating oil performance was studied. The results showed that the nanoparticles could act as "micro-ball bearings." (Gu Caixiang et al.)

[20] A study was conducted on nano-calcium carbonate and nano-rare earth composite lubricant additives. The results showed that nano-calcium carbonate acts as a "micro-ball" bearing and friction-reducing agent on the friction surface.

[0013] However, due to the strong van der Waals forces between nanospheres, aggregation and precipitation between nanospheres are easily caused, making the stability of nanosphere lubricating materials a huge challenge.

[21] To address this issue, researchers have explored methods such as adding dispersants, surface modification, and ultrasonic treatment to nanosphere lubricating materials. For example, He et al.

[22] Aqueous suspensions of Al₂O₃ nanoparticles of different sizes and concentrations were prepared. These suspensions were subjected to high-intensity ultrasonic treatment without further surface modification; however, the synthesized suspensions remained stable and sediment-free for only 3 days. For example, Wu et al.

[23] A water-based lubricating material made of titanium dioxide nanoparticles was developed. This lubricating material, treated with a surfactant (polyethyleneimine, PEI) and ultrasound, showed no deposition observed within just 7 days. Another example is Guo et al.

[24] Modifying ZnO and WS2 nanofluids with oleic acid and ionic liquids as surfactants, followed by ultrasonic stirring, resulted in no significant lamination observed within 10 days. However, numerous studies have shown that widely used surfactants, such as silane coupling agents, cannot generate sufficient steric repulsion to maintain the long-term stability of the nanofluids.

[21] On the other hand, the preparation process of nanospheres is complex and the preparation cost is high, making mass production impossible and limiting their application scope. More importantly, for lubricating materials that come into contact with human tissues and organs, nanospheres in the lubricating materials may also produce nanotoxicity to the human body, making it difficult to promote their application.

[0014] In summary, both the lubrication methods that reduce sliding friction and the lubrication methods that provide rolling friction have many defects. In summary, these defects are: (1) Lubricating materials with simple preparation methods usually do not have good lubrication effects; (2) Lubricating materials with good lubrication effects are either complicated in preparation process, have poor material stability, or are limited by the use environment. More importantly, their lubrication effect usually lasts for a short time.

[0015] It is evident that current research on lubricating materials primarily focuses on minimizing the coefficient of friction between materials while ensuring lubrication durability and stability, and improving the wear resistance and recyclability of lubricating materials. While surface coatings can achieve lubricating materials with lower coefficients of friction, these coatings are prone to peeling and wear, and require the construction of a base material. Surface modification methods can reduce friction between materials and address the issues of coating peeling and wear to some extent, but these methods are subject to significant limitations in terms of material types and application methods, and are also complex and costly.

[0016] In summary, while surface coating and surface modification methods can provide excellent lubrication, they suffer from complex processes, high costs, and limited application areas. Conversely, adding lubricants, although exhibiting drawbacks such as higher friction coefficients and limited lubrication effects, remains favored due to its simple preparation process, low cost, and wide range of applications. Silicone oil, as a commonly used lubricant, has been extensively used and researched. This invention primarily focuses on modifying silicone oil lubricants to provide a silicone oil-modified lubricant and product with excellent lubrication performance.

[0017] Silicone oil is a linear polyorganosiloxane with varying degrees of polymerization. It possesses excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, and physiological inertness; it also exhibits low surface tension, low temperature viscosity coefficient, oxidation resistance, high flash point, low volatility, and non-toxicity. Using silicone oil-based lubricants can achieve a low coefficient of friction that remains remarkably constant over a wide temperature range. However, current modified silicone oil-based lubricants still suffer from relatively high initial coefficients of friction and poor wear resistance stability, requiring the addition of substantial amounts of modifiers to significantly reduce the coefficient of friction and improve wear resistance.

[0018] For example, patent document CN105733754B provides an insulating grease containing fluorinated silicone oil and its preparation method. The resulting insulating grease has better high-temperature lubrication performance, higher anti-swelling and acid and alkali resistance, lower oil separation degree and friction coefficient. However, its friction coefficient tested at room temperature is still 0.23, and the friction coefficient measured at 200℃ is 0.45, indicating that its lubrication effect is relatively limited.

[0019] For example, patent document CN103242945B provides a phosphating bolt friction coefficient stabilizer, which forms a lubricating film that can maintain a friction coefficient of 0.06 to 0.09. However, the amount of silicone oil added in this friction coefficient stabilizer is small, while the amount of other modified additives is large, making it difficult to significantly improve the lubrication performance of silicone oil.

[0020] For example, patent document CN110591800A discloses a treadmill lubricant, which adds at least two silane coupling agents with different organic functional groups to silicone oil as a lubricant. The friction coefficient of this lubricant is <0.04, but the mass ratio of the two silane coupling agents is 10% to 20% of the lubricant. The amount added is relatively large, the cost is high, and the improvement of the lubrication effect of silicone oil is limited when added in small amounts.

[0021] Therefore, in view of the problems of existing silicone oil lubricants, such as high initial friction coefficient of silicone oil, poor wear resistance and stability, and large amount of modifier added and high cost, how to provide a silicone oil modified lubricant with simple preparation method, good modification effect of silicone oil, small amount added, low cost, and extremely low initial friction coefficient and wear resistance and stability has become the technical problem that this invention needs to solve.

[0022] The cited references are as follows:

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[0045]

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[0046]

[24] Guo J, Barber GC, Schall DJ, Zou Q, Jacob SB. Tribological properties of ZnO and WS2 nanofluids using different surfactants. Wear 2017;382:8e14. Summary of the Invention

[0047] The purpose of this invention is to solve the aforementioned technical problems, thereby providing a silicone oil-modified lubricant, its preparation method, and its application. The technical objective of this invention is twofold: firstly, to address the problems of existing silicone oil lubricants having a high initial coefficient of friction, poor wear resistance, and poor coefficient of friction maintenance; and secondly, to address the issues of existing silicone oil-modified lubricants requiring large amounts of modifier, resulting in high costs, and poor modification effects on silicone oil when added in very small quantities.

[0048] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0049] This invention first provides a method for preparing a silicone oil-modified lubricant, comprising the following steps:

[0050] (1) Dissolve hyaluronic acid in water to prepare a hyaluronic acid solution, then mix it with magnesium hydroxide solution, stir evenly, and place the mixed solution in an ice bath environment;

[0051] (2) Dissolve dodecanoyl chloride or stearyl chloride in 1,4-dioxane and add it dropwise to the mixture obtained in step (1) to carry out the reaction;

[0052] (3) After the reaction is complete, the product obtained in step (2) is concentrated, precipitated with ethanol, the precipitate is washed and dissolved with deionized water, and then freeze-dried to obtain silicone oil modified lubricant.

[0053] The method for preparing the silicone oil-modified lubricant provided by this invention uses hyaluronic acid as a raw material. This lubricant is prepared by mixing hyaluronic acid with a magnesium hydroxide solution and then reacting it with dodecanoyl chloride or stearyl chloride. This silicone oil-modified lubricant can spontaneously form ball bearings upon contact with water, providing rolling lubrication and significantly reducing friction. Its coefficient of friction can be as low as 0.048–0.056, exhibiting excellent stability and wear resistance. Only 0.1 wt%–1 wt% of the lubricant is required in the silicone oil (e.g., 0.5 wt% in the example) to achieve excellent lubrication.

[0054] Furthermore, the preparation method of the silicone oil-modified lubricant of this invention is simple, convenient, low in cost, and has a wide range of applications, whether for lubrication of mechanical equipment or biological materials; whether for in vitro or in vivo plant materials, it is not limited. This lubricant exhibits good stability, spontaneously forms ball bearings without agglomeration, and provides excellent rolling lubrication, thus maintaining interfacial lubrication performance for a long time.

[0055] As described in the embodiments, the silicone oil-modified lubricant provided by the present invention, combined with silicone oil, serves as a surface lubricant for medical catheters. It exhibits a low coefficient of friction, good stability of the coefficient of friction, and excellent long-term lubrication performance. Even at extremely low addition levels, it can achieve highly efficient modification of silicone oil lubricants, significantly improving their lubrication performance.

[0056] Furthermore, the concentration of the hyaluronic acid solution in step (1) is 10 mg / mL.

[0057] Furthermore, the concentration of the magnesium hydroxide solution in step (1) is 26.4 mg / mL.

[0058] Furthermore, the concentration of dodecanoyl chloride and 1,4-dioxane in step (2) is 16.25 mg / mL by mass-volume ratio.

[0059] Furthermore, the concentration of stearyl chloride and 1,4-dioxane in step (2) is 22.5 mg / mL by mass-volume ratio.

[0060] Furthermore, in step (3), the obtained product is filtered to remove impurities, and then concentrated by rotary evaporation at 65°C.

[0061] A second objective of this invention is to provide a silicone oil-modified lubricant, which is prepared by the method described above.

[0062] Specifically, the silicone oil-modified lubricant provided by this invention has the following structural formula <Ⅰ> or <Ⅱ>:

[0063]

[0064] A third objective of this invention is to provide a lubricant composition comprising a silicone oil-modified lubricant as shown in Formula or Formula <II> above, and silicone oil, wherein the silicone oil-modified lubricant accounts for 0.1-1 wt% of the total weight of the composition.

[0065] The fourth objective of this invention is to provide the application of the silicone oil modified lubricant or lubricant composition as described above in the preparation of medical catheter lubricants or lubricating coating materials.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] (1) The silicone oil modified lubricant and its composition provided by the present invention can spontaneously form balls and play the role of rolling lubrication, thereby greatly reducing friction. It has a small amount added to silicone oil and has the characteristics of excellent lubrication performance, good long-term lubrication effect and good stability.

[0068] (2) The preparation method of the silicone oil modified lubricant provided by the present invention is simple, the process is convenient, the preparation cost is low, and the application range is wide. It is not limited whether it is used for lubrication of mechanical equipment or lubrication of biological materials; whether it is for external lubrication or for internal plant materials, it can maintain the lubrication performance between interfaces well and can meet the lubrication needs of medical materials. Attached Figure Description

[0069] Figure 1 This is the hydrogen spectrum of hyaluronic acid;

[0070] Figure 2 The hydrogen spectrum of dodecanoyl chloride;

[0071] Figure 3 The hydrogen spectrum of hyaluronic acid-grafted lauric acid lubricant;

[0072] Figure 4 The hydrogen spectrum of hyaluronic acid-grafted stearic acid lubricant;

[0073] Figure 5 The results of the cycle number experiment for the lubricant prepared for the example. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in detail below with reference to embodiments. It should be noted that the following embodiments are merely for explanation and illustration and are not intended to limit the invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description are still within the scope of protection of this invention.

[0075] Example 1

[0076] A method for preparing a silicone oil-modified lubricant (using hyaluronic acid grafted with lauric acid) includes the following steps:

[0077] (1) Add 500 mg HA (hyaluronic acid) to 50 mL of deionized water and stir mechanically (110 rpm) until completely dissolved; weigh 132 mg Mg(OH)2 and suspend it in 5 mL of deionized water, add it to the reaction system, and rinse the EP tube with 5 mL of deionized water three times and add it to the reaction system in the same way; continue stirring until the system is homogeneous, and then place it in an ice bath;

[0078] (2) Weigh 325 mg of dodecanoyl chloride and dissolve it in 20 mL of 1,4-dioxane. Add the solution dropwise to the system using a dropping funnel to carry out the reaction.

[0079] (3) Post-processing: After the reaction, the product was filtered using a Buchner funnel to remove impurities. The filtrate was then concentrated by rotary evaporation (65°C), followed by precipitation with a large amount of ethanol to obtain a white flocculent precipitate. The supernatant was poured off, and the product was rinsed with ethanol, repeating this process three times. Finally, the solvent was completely removed by rotary evaporation, and the product was dissolved in deionized water and freeze-dried to obtain the silicone oil-modified lubricant of this invention—hyaluronic acid grafted lauric acid.

[0080] Test Example 1

[0081] Figure 1 and Figure 2 The 1H NMR spectra of hyaluronic acid and dodecanoyl chloride are shown separately. Figure 3 The 1H NMR spectrum results of the hyaluronic acid-grafted lauric acid lubricant prepared in Example 1 are shown. Figure 3 It can be seen that at point a: 3H, at point b: 3H, and the grafting rate is calculated as follows:

[0082] Grafting rate = A b / A a ×100%=0.33 / 1.00×100%=33%.

[0083] Example 2

[0084] A method for preparing a silicone oil-modified lubricant (hyaluronic acid-linked stearyl chloride) includes the following steps:

[0085] (1) Add 500 mg HA to 50 mL of deionized water and stir mechanically (110 rpm) until completely dissolved. Weigh 132 mg Mg(OH)2, suspend and dissolve it in 5 mL of deionized water, add it to the reaction system, and rinse the EP tube three times with 5 mL of deionized water and add it to the reaction system. Continue stirring until the system is homogeneous, and then place it in an ice bath.

[0086] (2) Weigh 450.7 mg stearyl chloride and dissolve it in 20 mL of 1,4-dioxane. Add the solution dropwise to the system using a dropping funnel to carry out the reaction.

[0087] (3) Post-processing procedure: After the reaction is completed, the product is filtered using a Buchner funnel to remove impurities. The filtrate is concentrated by rotary evaporation (65°C), followed by precipitation with a large amount of ethanol to obtain a white flocculent precipitate. The supernatant is decanted, and the product is rinsed with ethanol, repeating this process three times. Finally, the solvent is completely removed by rotary evaporation, and the product is dissolved in deionized water and freeze-dried to obtain the silicone oil modified lubricant of this invention—hyaluronic acid-stearyl chloride.

[0088] Test Example 2

[0089] The results of 1H NMR spectroscopy of hyaluronic acid grafted with stearic acid are as follows: Figure 4 As shown. It can be seen that at point a: 3H, at point b: 3H, the grafting rate is calculated as follows:

[0090] Grafting rate = A b / A a ×100%=0.51 / 1.00×100%=51%.

[0091] Experimental Example 1

[0092] The surface tribological properties and long-term cyclic properties of materials were tested using a reciprocating sliding friction and wear test in a ball-plane contact mode on a UMT-TriboLab multifunctional friction and wear testing machine. Silicone oil 120cp (Si 1) or a silicone oil-modified lubricant prepared in the examples + silicone oil (120cp silicone oil with the silicone oil-modified lubricant of Example 1 or Example 2 added, wherein the concentration of the silicone oil-modified lubricant is 0.5wt%) (Si 3) was added to a flat polyurethane film. The friction pair consisted of PDMS balls with a diameter of 6 mm, a normal load of 0.5 N, a reciprocating displacement of 2 mm, a frequency of 2 Hz, and a reciprocating sliding time of 2500 s. Three samples were tested for each condition.

[0093] Test results are available Figure 5 ,from Figure 5 It can be seen that after adding the silicone oil modified lubricant of the present invention, the friction coefficient can be maintained at 4 times lower than that of pure silicone oil in 5000 friction tests, and the friction coefficient can be maintained continuously.

[0094] Experiment Example 2

[0095] The friction coefficients of the silicone oil-modified lubricants prepared in Examples 1 and 2 were tested and compared with those of traditional silicone oil lubricants. The experimental methods are as follows:

[0096] 1. Traditional lubricant: Silicone oil 120cp

[0097] 2. Silicone oil modified lubricant composition: 120cp silicone oil + silicone oil modified lubricant (the schemes in Examples 1-2, where the mass percentage of silicone oil modified lubricant is 0.5wt%)

[0098] 3. Friction coefficient testing method:

[0099] (1) Pour the prepared lubricant onto the nonwoven fabric.

[0100] (2) Use a non-woven fabric (already impregnated with lubricant) to coat a thermoplastic polyurethane (TPU) conduit with no obvious defects on the surface, so that a layer of lubricant is attached to the surface of the TPU conduit.

[0101] (3) Turn on the friction coefficient testing equipment (equipment name: vertical fully automatic friction tester, FW-02, Jiangsu Baisaifei Biotechnology Co., Ltd.)

[0102] (4) Set device parameters:

[0103] Clamping force: 3.0N, stretching speed: 3.33mm / s, mode: dry test, number of cycles: 3.

[0104] (5) The friction coefficient test results of all samples are shown in Table 1.

[0105] Table 1

[0106]

[0107] As can be seen from the results in Table 1, the average friction coefficient of pure silicone oil is nearly 4 times that of silicone oil modified lubricant prepared according to the present invention (only 0.5 wt%). Furthermore, the product friction coefficient stability is better after adding the silicone oil modified lubricant composition of the present invention (i.e., the fluctuation between the highest and lowest friction coefficients is smaller).

Claims

1. A method for preparing a silicone oil-modified lubricant, characterized in that, Includes the following steps: (1) Dissolve hyaluronic acid in water to prepare a hyaluronic acid solution, then mix it with magnesium hydroxide solution, stir evenly, and place the mixed solution in an ice bath environment; (2) Dissolve dodecanoyl chloride or stearyl chloride in 1,4-dioxane and add it dropwise to the mixture obtained in step (1) to carry out the reaction; (3) After the reaction is complete, the product obtained in step (2) is concentrated, precipitated with ethanol, the precipitate is washed and dissolved with deionized water, and then freeze-dried to obtain silicone oil modified lubricant.

2. The preparation method according to claim 1, characterized in that, The concentration of the hyaluronic acid solution mentioned in step (1) is 10 mg / mL.

3. The preparation method according to claim 1, characterized in that, The concentration of the magnesium hydroxide solution in step (1) is 26.4 mg / mL.

4. The preparation method according to claim 1, characterized in that, The concentration of dodecanoyl chloride and 1,4-dioxane in step (2) is 16.25 mg / mL by mass-volume ratio.

5. The preparation method according to claim 1, characterized in that, The concentration of stearyl chloride and 1,4-dioxane in step (2) is 22.5 mg / mL by mass-volume ratio.

6. The preparation method according to claim 1, characterized in that, In step (3), the obtained product is filtered to remove impurities, and then concentrated by rotary evaporation at 65°C.

7. A silicone oil-modified lubricant, characterized in that, It is prepared by the method described in any one of claims 1-6.

8. The silicone oil-modified lubricant according to claim 7, characterized in that, The structural formula of the silicone oil-modified lubricant is shown in formula <Ⅰ> or formula <Ⅱ> below:

9. A lubricant composition, characterized in that, The composition comprises a silicone oil-modified lubricant as described in claim 7 or 8 and a silicone oil, wherein the silicone oil-modified lubricant comprises 0.1-1% of the total weight of the composition.

10. The use of the silicone oil modified lubricant of claims 7-8 or the lubricant composition of claim 9 in the preparation of medical catheter lubricants or lubricating coating materials.

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