String care nanoemulsion and method of making same

Abstract

The present application relates to string maintenance nanoemulsion and its preparation method, belong to string maintenance technical field. The nanoemulsion includes: polysorbate 80, stearic acid sorbitan 60 as main emulsifier, glycerin monostearate, cetyl alcohol, stearyl alcohol as auxiliary emulsifier, liquid paraffin, xanthan gum adjusts consistency, chitosan carries sodium hyaluronate nanoparticle as long-acting moisturizing agent, glycerol, propylene glycol is humectant and can be used as antifreezing agent; hydroxyphenyl ethyl as preservative; can also selectively add essence, the balance is water. The water-soluble ingredients are mixed and stirred uniformly; the oil-soluble ingredients are mixed and stirred uniformly; the oil phase is added to the water phase, and the primary emulsion is stirred and emulsified, and the essence is added after cooling, and the present application is obtained. The present application realizes long-acting moisturizing and nourishing of the string by introducing chitosan carrying sodium hyaluronate nanoparticles, and has the advantages of fine texture, softness and the like.

Description

Technical Field

[0001] The invention relates to a piano string maintenance nanoemulsion and a preparation method thereof, belonging to the technical field of piano string maintenance. Background Art

[0002] Guqin, guzheng, and pipa strings were traditionally made primarily of mulberry silk. While their sound was soft and elegant, they were also low-volume and prone to breaking during playing. Therefore, modern strings are mostly nylon-wrapped metal, balancing durability and timbre. However, modern strings, especially new ones, can produce a dry, metallic sound. Currently, applying vaseline is commonly used to reduce noise. However, vaseline is very greasy, attracts dust, and is difficult to wipe clean. Furthermore, vaseline clumps in winter and melts in summer, making it inconvenient to use. It's also difficult to control the amount of permeation, and excessive use can affect string vibration and make the sound muffled. Compared to vaseline, emulsion has a lighter texture, a moderate degree of permeability, and its properties don't change with temperature. After properly adjusting the bridge and strings, apply an appropriate amount of string conditioning lotion to the string surface, combined with vigorous playing to ensure full string vibration. This can effectively reduce noise, enhance the warmth of the tone, and help the instrument mature and extend its lifespan. For example, CN108823978A discloses a string-protecting lotion, comprising lanolin, glycerin, white oil, stearyl alcohol, cetyltrimethylammonium chloride, polyethylene glycol, 5-urea-hydantoin, essence, and pigment; the mixture is mixed in the following proportions by weight: the percentage of lanolin is 0.5-1.5, the percentage of glycerin is 4-8, the percentage of white oil is 0.5-2, the percentage of stearyl alcohol is 0.5-2, the percentage of cetyltrimethylammonium chloride is 1.2-2.5, the percentage of polyethylene glycol is 0.5-2, the percentage of 5-urea-hydantoin is 0.2-0.8, the percentage of essence is 0.01-0.012, the percentage of pigment is 0.0004-0.00006, and deionized water is the balance. CN108998969A discloses a violin wax emulsion, comprising liquid wax, carnauba wax, beeswax, spermaceti, cetyl alcohol, polyethylene glycol, bleached shellac, nonylphenol polyoxyethylene ether, borax, and cetyltrimethylammonium chloride. The composition percentage by mass of the violin wax emulsion is as follows: liquid wax: 4-8%, carnauba wax: 5-8%, beeswax: 4-8%, spermaceti: ​​1-4%, cetyl alcohol: 2-3%, polyethylene glycol: 0.8-2%, shellac: 0.5-5%, nonylphenol polyoxyethylene ether: 2-4%, borax: 2-3.5%, cetyltrimethylammonium chloride: 1-2.5%, fragrance: 0.01-0.02%, and water: the remainder. The shellac is bleached shellac.CN109252362A discloses a preparation process of protective liquid wax emulsion, first put 1 / 5 of water in the water formula into a heating tank, heat to 60±5℃, add 0.5~5% of shellac into the heating tank and stir until the shellac is dissolved into colloid; put the prepared colloid into a batching tank, add liquid wax, Brazil palm wax, beeswax, whale wax, cetyl alcohol, polyethylene glycol, nonylphenol polyoxyethylene ether, borax, cetyltrimethylammonium chloride under stirring; add the remaining water, cool the mixed material to room temperature; add spices, open the batching valve at the bottom of the batching tank, and pump the material in the batching tank into the aging tank for aging; after the material is aged, pressurize the aging tank, open the filling valve, and send the aged material to the filling machine for filling.

[0003] However, the existing protective products for strings mainly have the following defects: the stability of ordinary emulsion is low, and delamination phenomenon is easy to occur; and the moisturizing time is short, and frequent use is required. The string care paste has high concentration, slow penetration speed, and is easy to absorb dust. SUMMARY

[0004] In view of the above prior art, the present application finds that the emulsion is prepared into a nano emulsion, and the ultra-small particle size can significantly delay aggregation or delamination. Chitosan (CS) is used to encapsulate sodium hyaluronate (SH) to prepare chitosan / sodium hyaluronate (CS / SH) nanoparticles. The CS / SH nanoparticles not only enhance the stability of sodium hyaluronate in the emulsion system, but also enhance the ability of the emulsion to absorb moisture from the surrounding environment and delay the release of moisture from the emulsion system, so that the emulsion continuously has a moisturizing function. Through the synergistic effect of the complex emulsifier and the precise control of the process parameters, the stability of the emulsion system is improved. The present application is completed based on the above findings.

[0005] Therefore, one object of the present application is to provide a string care nano emulsion which has thermodynamic stability, is not prone to delamination, has good spreading, dispersing and long-acting moisturizing properties.

[0006] Another object of the present application is to provide a preparation method of the string care nano emulsion, which realizes the improvement of the stability of the emulsion system through the synergistic effect of the complex emulsifier and the precise control of the process parameters. The defect of poor storage stability existing in the conventional emulsification method is effectively solved.

[0007] The technical solutions for achieving the above-mentioned application objectives can be summarized as follows:

[0008] The string care nano emulsion comprises an aqueous phase and an oil phase, and the percentage of each component in the total mass of the nano emulsion is as follows:

[0009] The water phase comprises: water 35%-45%, xanthan gum 3%-5%, CS / SH nanoparticles 1.5%-3.5%, glycerol 5%-15%, propylene glycol 2%-5%, hydroxyphenyl ethyl ester 0.1%-0.5%, polysorbate 80 15%-25%;

[0010] The oil phase comprises: sorbitan stearate 60 0%-6%, glycerol monostearate 0.4%-2%, cetyl alcohol 0.05%-0.8%, stearyl alcohol 0.05%-0.5%, liquid paraffin 15%-40%.

[0011] According to the application, preferably, the water phase is 65%-75% and the oil phase is 25%-35% in percentage of total mass of the nanoemulsion.

[0012] According to the application, preferably, the total mass percentage of polysorbate 80 and sorbitan stearate 60 is 15%-28%.

[0013] According to the application, preferably, the CS / SH nanoparticles are prepared by using ion gel method with chitosan as carrier material and sodium tripolyphosphate (TPP) as crosslinking agent.

[0014] Further preferably, the CS / SH nanoparticles are prepared by the following method:

[0015] The sodium hyaluronate aqueous solution and the chitosan glacial acetic acid solution are mixed together, and the TPP aqueous solution is added drop by drop under stirring, and the reaction is carried out at 30-40 DEG C, the mass percentage of sodium hyaluronate to chitosan is 3%-8%, and the mass ratio of chitosan to TPP is (5-7):1; after the reaction is completed, the insoluble impurities are removed by filtration, and the unreacted small molecule substances are removed by dialysis to obtain the chitosan / sodium hyaluronate nanoparticles.

[0016] More preferably, the concentration of the TPP solution is 0.5 mg / mL-1.0 mg / mL, the chitosan glacial acetic acid solution is prepared by dissolving chitosan in a glacial acetic acid solution with a mass fraction of 1% and a pH of 4, and the concentration of the chitosan glacial acetic acid solution is 1.5 mg / mL-2.5 mg / mL.

[0017] According to the application, preferably, the violin string curing nanoemulsion further comprises 0.05%-0.2% of essence in percentage of total mass of the nanoemulsion.

[0018] According to the application, the preparation method of the violin string curing nanoemulsion comprises the following steps:

[0019] Water phase preparation: heat water to 55~60℃, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, hydroxyphenyl ethyl ester, polysorbate 80 in sequence, stir to dissolve uniformly to form a water phase;

[0020] Oil phase preparation: heat stearic acid sorbitan 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, liquid paraffin to 60~65℃, stir to dissolve uniformly to form an oil phase;

[0021] Primary emulsion preparation: under stirring at 60~65℃, add the water phase to the oil phase, and when the water phase is greater in mass than the oil phase, phase inversion occurs to form an oil-in-water emulsion (oil, O; water, W; oil-in-water, O / W);

[0022] Emulsification and homogenization: after the system temperature is reduced to 40~50℃, intermittent emulsification is performed, and after intermittent emulsification, cooling is performed to room temperature to obtain the string maintenance nanoemulsion.

[0023] According to the present application, preferably, in the primary emulsion preparation process, the water phase is added to the oil phase at a speed of 1~2 mL / s, the stirring speed is controlled at 500~800 rpm, and the emulsification time is controlled at 10~15 min.

[0024] According to the present application, preferably, in the emulsification and homogenization process, after the system temperature is reduced to 40~50℃, the essence is added, and then intermittent emulsification is performed; further preferably, the rotation speed of intermittent emulsification is 1500~2500 rpm, and the emulsification time is 5~10 min; more preferably, the cooling rate after intermittent emulsification is 3~5℃ per minute.

[0025] The present application has the following beneficial effects:

[0026] 1. The string maintenance nanoemulsion of the present application is a nanoemulsion, and the ultra-small particle size can significantly delay aggregation or delamination, so that the nanoemulsion can maintain physical stability for months or even years without flocculation or coalescence.

[0027] 2. The present application uses CS / SH nanoparticles, and the chitosan nanoparticles encapsulate sodium hyaluronate, which not only enhances the stability of sodium hyaluronate in the nanoemulsion system, but also enhances the ability of the emulsion to absorb moisture from the surrounding environment and delays the release of moisture from the emulsion system, so that the emulsion continuously has a moisturizing function.

[0028] 3. This invention utilizes the combined use of polysorbate 80 and sorbitan stearate 60 to adjust the HLB value of the nanoemulsion. Polysorbate 80 reduces the surface tension of the aqueous phase, while sorbitan stearate 60 reduces the surface tension of the oil phase. Their combined use creates a synergistic effect. This avoids the low viscosity and storage stratification that can occur with the oil-in-water emulsifier polysorbate 80 alone, resulting in a more stable emulsion system. Excipients such as glyceryl monostearate, cetyl alcohol, and stearyl alcohol further enhance the mechanical strength of the interfacial film.

[0029] 4. This invention utilizes an innovative emulsification solution, leveraging the synergistic effects of composite emulsifiers combined with precise control of process parameters to enhance the stability of the emulsion system. This effectively addresses the storage stability deficiencies of conventional emulsification methods and provides reliable process support for industrial production.

[0030] 5. The optimized ratio of the aqueous and oil phases in this guitar string care nanoemulsion successfully imparts a uniquely lightweight and comfortable feel. This formulation achieves the dual effects of smooth spreading and penetration across the string surface, avoiding the stickiness and heaviness associated with traditional guitar care creams and oils, fully satisfying modern consumers' dual expectations for both freshness and efficacy in guitar care products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 These are appearance photos of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0032] Figure 2 This is a graph showing the particle size test results of Example 1. DETAILED DESCRIPTION

[0033] The present invention provides a guitar string care nanoemulsion and a preparation method thereof, which solves the problems of low stability, easy stratification, short moisturizing time and frequent use of conventional guitar care products such as ordinary emulsions. The guitar string care emulsion has long-lasting moisturizing, good permeability and improved stability, and belongs to an oil-in-water emulsion system.

[0034] The string maintenance nanoemulsion of the present invention comprises an aqueous phase and an oil phase, and the percentage of the total mass of the nanoemulsion is:

[0035] The aqueous phase comprises: 35% to 45% water, 3% to 5% xanthan gum, 1.5% to 3.5% CS / SH nanoparticles, 5% to 15% glycerol, 2% to 5% propylene glycol, 0.1% to 0.5% ethylparaben, and 15% to 25% polysorbate 80;

[0036] The oil phase comprises: sorbitan stearate 600%-6%, glyceryl monostearate 0.4%-2%, cetyl alcohol 0.05%-0.8%, stearyl alcohol 0.05%-0.5%, and liquid paraffin 15%-40%.

[0037] In one or more preferred embodiments, based on the percentage of the total mass of the nanoemulsion, the water phase is 65% to 77%, and the oil phase is 23% to 35%.

[0038] According to the present invention, polysorbate 80 and sorbitan stearate 60 are used together to adjust the HLB (Hydrophile-Lipophile Balance) value of the nanoemulsion. The HLB value quantifies the balance between the hydrophilicity and lipophilicity of a surfactant, guiding its application. In the standard system, paraffin has an HLB of 0 (completely lipophilic) and polyethylene glycol has an HLB of 20 (completely hydrophilic). Polysorbate 80 reduces the surface tension of the aqueous phase, while sorbitan stearate 60 reduces the surface tension of the oil phase. Their combined use produces a synergistic effect. This avoids the low viscosity and storage stratification that can occur when using polysorbate 80 alone as an O / W emulsifier, resulting in a more stable emulsion system.

[0039] In one or more preferred embodiments, the total mass percentage of polysorbate 80 and sorbitan stearate 60 is 15% to 28%. Preferably, the HLB value of the nanoemulsion is 13 to 18.

[0040] According to the present invention, chitosan / sodium hyaluronate nanoparticles are the core component for achieving long-lasting moisturizing of the emulsion. Chitosan is used as a carrier material, TPP is used as a cross-linking agent, and the CS / SH nanoparticles are prepared by an ion gel method.

[0041] In one or more preferred embodiments, CS / SH nanoparticles are prepared as follows:

[0042] A sodium hyaluronate aqueous solution and a chitosan glacial acetic acid solution are mixed together, and a TPP aqueous solution is added dropwise under stirring conditions. The reaction is carried out at 30°C to 40°C. The mass percentage of sodium hyaluronate to the mass of chitosan is 3% to 8%, and the mass ratio of chitosan to TPP is (5-7):1. After the reaction is completed, insoluble impurities are removed by filtration, and unreacted small molecules are removed by dialysis to obtain chitosan / sodium hyaluronate nanoparticles.

[0043] More preferably, the concentration of the TPP solution is 0.5 mg / mL to 1.0 mg / mL, the chitosan glacial acetic acid solution is chitosan dissolved in a glacial acetic acid solution with a pH of 4 and a mass fraction of 1%, and the concentration of the chitosan glacial acetic acid solution is 1.5 mg / mL to 2.5 mg / mL.

[0044] In one or more preferred embodiments, the preparation steps of CS / SH nanoparticles are as follows:

[0045] (1) Preparation of TPP solution: accurately weigh TPP particles to prepare a 0.5 mg / mL ~1.0 mg / mL solution in deionized water.

[0046] (2) Preparation of 1% glacial acetic acid solution, adjust pH to 4.0 with 1 mol / L NaOH.

[0047] (3) Preparation of chitosan solution: accurately weigh an appropriate amount of chitosan and dissolve it in the above glacial acetic acid solution to prepare a solution with a concentration of 1.5 mg / mL ~2.5 mg / mL, reaction temperature 37 ℃, magnetic stirring at 1000 rpm for 1 h.

[0048] (4) Preparation of sodium hyaluronate solution, concentration 1~3%.

[0049] (5) Mix the sodium hyaluronate solution and the chitosan solution together, the mass percentage of sodium hyaluronate in chitosan is 3%~8%, the mass ratio of chitosan to TPP is 6:1, use a syringe to add TPP solution drop by drop into the chitosan / sodium hyaluronate solution, stir while adding, reaction temperature 37 ℃, magnetic stirring at 1000 rpm for 1 h.

[0050] (6) After the reaction is completed, filter with a filter membrane to remove insoluble impurities. The filtered solution is dialyzed with a dialysis bag to remove unreacted small molecule substances, replace the dialysis fluid every 2 h, and dialyze for 12 h. The dialyzed solution is filtered again with a filter membrane to obtain CS / SH nanoparticles.

[0051] In a preferred embodiment, the CS / SH nanoparticles are slowly dispersed and scattered into heated deionized water, and stirred for 5 min~10 min to ensure uniform dispersion. Chitosan acts as a carrier to encapsulate sodium hyaluronate, avoiding direct contact with the external environment, thereby improving its stability in the cream system. As the chitosan carrier material gradually degrades, sodium hyaluronate is slowly released. Sodium hyaluronate is composed of alternating arrangements of glucuronic acid and N-acetylglucosamine, and its molecular surface contains a large number of hydrophilic groups (hydroxyl -OH), which can bind a large number of water molecules through hydrogen bonds, and absorb water from the external environment. The viscoelasticity of sodium hyaluronate allows it to dynamically adjust water absorption / release according to the environmental humidity: it absorbs water in high humidity and slowly releases water in low humidity, thereby achieving the long-acting moisturizing function of the emulsion.

[0052] In one or more preferred embodiments, the molecular weight of the CS / SH nanoparticles is 100 kDa ~150 kDa.

[0053] In one or more preferred embodiments, the string care nanoemulsion further comprises 0.05%-0.2% of a fragrance, calculated as a percentage of the total mass of the nanoemulsion. Other ingredients in the emulsion may have natural odors, and the fragrance can effectively neutralize or mask these unpleasant odors, enhancing the sensory experience of the product.

[0054] According to the present invention, water, preferably deionized water, serves as the primary solvent of the aqueous phase and as a carrier for the uniform dispersion of other water-soluble ingredients. Deionized water prevents ionic interference from chemical reactions, safeguards the physical stability of the system, and ensures the purity and sensory quality of the product. Furthermore, within this temperature range, it effectively dissolves CS / SH nanoparticles, glycerol, and other water-soluble ingredients without degrading the active ingredients.

[0055] Deionized water removes anionic and cationic impurities through ion exchange resins or reverse osmosis processes, but it cannot effectively intercept soluble organic matter and microorganisms. Its pure nature, however, creates a non-competitive environment for bacterial growth. Residual organic matter can serve as nutrients for microbial growth. Therefore, nanoemulsions incorporate the commonly used preservative ethylparaben to extend the product's shelf life by inhibiting microbial growth.

[0056] Alternatively, in one or more preferred embodiments, glycerin and propylene glycol are added. Glycerin and propylene glycol are commonly used auxiliary moisturizers that promote the penetration of other moisturizing ingredients in the emulsion, enhancing the overall moisturizing effect. Glycerin and propylene glycol also have an antifreeze function. The amount of glycerin and propylene glycol is adjusted appropriately based on the target moisturizing time of the emulsion to ensure the appropriate texture.

[0057] Xanthan gum is widely used in emulsions, has stable physical and chemical properties, a significant thickening effect, and good suspending and emulsifying properties, making it an excellent thickener and stabilizer. Therefore, the present invention uses xanthan gum as a thickener to increase the stability of the emulsion. During use, the xanthan gum is evenly sprinkled on the deionized water surface, avoiding contact with the vessel wall. It is best to allow it to swell for two to three minutes before stirring to dissolve.

[0058] The aqueous phase in the present invention provides a pure environment through dual protection of deionized water and ethylparaben, and the synergistic effect of CS / SH nanoparticles, glycerin and propylene glycol provides long-lasting moisturizing. The thickening function of xanthan gum increases the stability of the system, laying a solid foundation for the emulsification process of the emulsion.

[0059] According to the present invention, the oil phase comprises sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin as core ingredients, and is formed into a uniformly dispersed oil phase through heating and stirring. The selection of oil phase ingredients and the preparation process directly influence the stability and permeability of the guitar string care nanoemulsion.

[0060] Liquid paraffin serves as a carrier for uniformly dispersing other fat-soluble components in the oil phase. Its chemical inertness ensures it does not react chemically with other ingredients. Liquid paraffin is the foundational carrier of the emulsification system. By adjusting the liquid paraffin content, the size and uniformity of the emulsion droplets can be controlled, directly impacting the emulsion's physical stability and resistance to stratification during storage. Liquid paraffin and emulsifiers synergistically reduce interfacial tension, promote uniform dispersion of the oil and water phases, and form a stable dispersion system with the aqueous phase.

[0061] Glyceryl monostearate has dual emulsifying and stabilizing properties. In oil-in-water emulsions, it thickens and enhances the emulsion's smoothness. It promotes uniform dispersion of oil and water, improving product ductility and texture. It also synergizes with the primary emulsifier, optimizing interfacial film strength, increasing system stability, and extending the emulsion's shelf life.

[0062] Cetyl alcohol and stearyl alcohol can be used as thickeners in guitar string conditioners, enhancing the emulsion's smoothness. While used in combination, they each focus on different functions. Stearyl alcohol primarily increases the viscosity and water absorption capacity of the oil phase, enhancing the emulsion's hardness and aiding moisturizing in oil-in-water (O / W) matrices. Cetyl alcohol improves the emulsion's smoothness, imparting a smooth texture and reducing waxy stickiness. It also acts as a penetration enhancer. A cetyl alcohol to stearyl alcohol ratio of approximately 7:3 provides both thickening and emulsification, preventing oil-water separation and exhibiting a "post-thickening" property (slowly increasing in consistency after standing).

[0063] According to the present invention, the preparation method of the above-mentioned guitar string maintenance nanoemulsion comprises the following steps:

[0064] Preparation of aqueous phase: Heat water to 55°C~60°C, add xanthan gum, CS / SH nanoparticles, glycerin, propylene glycol, ethylparaben, and polysorbate 80 in sequence, stir and dissolve evenly to form an aqueous phase;

[0065] Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 60°C~65°C, stir and dissolve evenly to form an oil phase;

[0066] Colostrum preparation: Add the water phase to the oil phase under stirring at 60℃~65℃. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an oil-in-water emulsion.

[0067] Emulsification and homogenization: After the system temperature drops to 40°C~50°C, intermittent emulsification is carried out, and after intermittent emulsification, it is cooled to room temperature to obtain the guitar string maintenance nanoemulsion.

[0068] According to the present invention, water serves as a carrier for uniformly dispersing other water-soluble ingredients. The water is heated to 55°C–60°C to dissolve the aqueous phase components. Each step in the aqueous phase preparation is precisely controlled according to preset temperature parameters and time standards to ensure optimal efficacy of each active ingredient. In particular, the uniformity of the dispersion of xanthan gum and CS / SH nanoparticles in the system affects their distribution stability within the emulsion, and thus their moisturizing properties.

[0069] According to the present invention, the oil phase heating temperature is set between 60°C and 65°C for two key considerations: first, this temperature range allows solid raw materials such as glyceryl monostearate to reach a complete melt state; second, it effectively prevents cetyl alcohol and stearic acid from undergoing structural changes or activity reduction at high temperatures. This temperature control strategy establishes an ideal pretreatment environment for the emulsification system, ensuring uniform dispersion of the oil phase components while mitigating the risks to emulsification system stability caused by improper temperature.

[0070] Under specific experimental conditions, the oil-phase mixing process focuses on precise control of mechanical stirring parameters. Research has shown that a proper ratio of agitator speed and duration can significantly improve the dispersion of oil-phase components within the emulsified system, which is crucial for forming a uniform and stable emulsion microstructure. Based on experimental validation, optimizing the mixing time to 15-20 minutes ensures ideal intermolecular bonding between the components.

[0071] According to the present invention, the core of emulsification lies in slowly adding the prepared aqueous phase to the continuously stirred oil phase. In one or more preferred embodiments, during colostrum preparation, the aqueous phase is added to the oil phase at a rate of 1-2 mL / s, with stirring speed controlled between 500 and 800 rpm, and the emulsification time controlled between 10 and 15 minutes. Initially, a W / O colostrum forms. As the aqueous phase gradually increases, the colostrum transforms into an O / W colostrum. The stirring time is 10-15 minutes to ensure complete mixing of the oil and aqueous phases, resulting in a fine-textured colostrum.

[0072] In one or more preferred embodiments, the temperature during colostrum preparation is controlled at 60° C. to 65° C., which is conducive to the full dispersion of the oil phase components in the aqueous phase and can avoid high-temperature degradation or inactivation of components such as sodium hyaluronate.

[0073] After the colostrum is prepared, the system temperature is lowered to 40℃ ~ 50℃, and high-speed intermittent emulsification is performed. After cooling to room temperature, a fine and stable nano-emulsion system can be obtained.

[0074] Specifically, during colostrum preparation, the aqueous phase is slowly added to the oil phase, effectively preventing uneven emulsion particles from forming due to vigorous interaction between the oil and aqueous phases. The stirring speed is gradually increased from 500 rpm for basic mixing to 800 rpm to enhance emulsification and improve the uniformity and stability of the emulsion system. The emulsification time is controlled at 10-15 minutes, ensuring that the oil phase particles are fully dispersed and evenly coated in the aqueous phase, forming a relatively stable colostrum system.

[0075] In one or more preferred embodiments, after the system temperature drops to 40°C~50°C during the emulsification and homogenization process, flavor is further added, and then intermittent emulsification is performed; preferably, the rotation speed of intermittent emulsification is 1500 rpm~2500 rpm, and the emulsification time is 5 min~10 min; more preferably, the cooling rate after intermittent emulsification is 3°C~5°C per minute.

[0076] In some embodiments, optical microscopy reveals that the colostrum is uniformly distributed, with no apparent aggregation or stratification. The emulsification and homogenization process is crucial for colostrum formation. Due to the high-speed stirring and rapid heat dissipation involved, this process requires relatively low ambient temperatures.

[0077] The optimization of the emulsification step of the present invention is mainly achieved through the following process improvements: first, by precisely controlling the temperature and stirring speed, the emulsion particles are ensured to be fine and evenly distributed; second, the synergistic emulsifiers polysorbate 80 and sorbitan stearate 60 are used to reduce the tension at the oil-water interface and improve the stability of the emulsion; finally, the water phase is gradually added to the oil phase to cause the emulsion to transform, so that the system is evenly emulsified.

[0078] This invention significantly improves the stability and functional performance of the string-care nanoemulsion through scientific emulsification operation design and technical parameter control. The stability of the emulsion system is enhanced through improved temperature control, optimized stirring, and synergistic effects of the emulsifier.

[0079] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementation cases obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0080] Example 1

[0081] In this embodiment, the ratio is that the water phase accounts for 74.52% of the total weight of the emulsion, and the oil phase accounts for 25.38% of the total weight of the emulsion.

[0082] In the aqueous phase, deionized water accounts for 40.11% of the total weight, CS / SH nanoparticles account for 2.26% of the total weight, glycerol accounts for 9.00% of the total weight, propylene glycol accounts for 3.50% of the total weight, xanthan gum accounts for 4.33% of the total weight, ethylparaben accounts for 0.20% of the total weight, and polysorbate 80 accounts for 15.12% of the total weight;

[0083] In the oil phase, sorbitan stearate 60 accounts for 1.68% of the total weight, glyceryl monostearate accounts for 0.79% of the total weight, cetyl alcohol accounts for 0.10% of the total weight, stearyl alcohol accounts for 0.21% of the total weight, and liquid paraffin accounts for 22.60% of the total weight.

[0084] The preparation process includes:

[0085] (1) Preparation of aqueous phase: Heat deionized water to 60°C, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, ethylparaben, and polysorbate 80 in sequence, and stir at 600 rpm to dissolve evenly to form an aqueous phase.

[0086] (2) Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 67°C and stir at 600 rpm to dissolve them uniformly to form an oil phase.

[0087] (3) Preparation of colostrum: At 60°C, slowly add the water phase to the stirring oil phase, and gradually increase the rotation speed from 500 to 800 rpm. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an O / W emulsion.

[0088] (4) Emulsification and homogenization: Emulsify at 2000 rpm for 12 min at 60°C. Lower the system temperature to 40-50°C, add 0.1% of the total weight of flavor, stir evenly at 600 rpm until dissolved, and cool to room temperature to obtain a nano-emulsion system.

[0089] Example 2

[0090] In this embodiment, the ratio is that the water phase accounts for 75.68% of the total weight of the emulsion, and the oil phase accounts for 24.22% of the total weight of the emulsion.

[0091] In the aqueous phase, deionized water accounts for 42.00% of the total weight, CS / SH nanoparticles account for 3.26% of the total weight, glycerol accounts for 9.00% of the total weight, propylene glycol accounts for 3.00% of the total weight, xanthan gum accounts for 4.00% of the total weight, ethylparaben accounts for 0.20% of the total weight, and polysorbate 80 accounts for 14.22% of the total weight;

[0092] In the oil phase, sorbitan stearate 60 accounts for 1.58% of the total weight, glyceryl monostearate accounts for 0.64% of the total weight, cetyl alcohol accounts for 0.08% of the total weight, stearyl alcohol accounts for 0.22% of the total weight, and liquid paraffin accounts for 21.70% of the total weight.

[0093] The preparation process includes:

[0094] (1) Preparation of aqueous phase: Heat deionized water to 62°C, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, ethylparaben, and polysorbate 80 in sequence, and stir at 700 rpm to dissolve evenly to form an aqueous phase.

[0095] (2) Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 66°C and stir at 700 rpm to dissolve them uniformly to form an oil phase.

[0096] (3) Preparation of colostrum: At 61°C, slowly add the water phase to the stirring oil phase, and gradually increase the rotation speed from 500 rpm to 800 rpm. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an O / W emulsion.

[0097] (4) Emulsification and homogenization: Emulsify at 50℃ and 2000 rpm for 10 min. Then reduce the system temperature to 40℃~50℃, add 0.1% of the total weight of flavor, stir evenly at 600 rpm until dissolved, and cool to room temperature to obtain a nano-emulsion system.

[0098] Example 3

[0099] In this embodiment, the ratio is that the water phase accounts for 76.85% of the total weight of the emulsion, and the oil phase accounts for 23.05% of the total weight of the emulsion.

[0100] In the aqueous phase, deionized water accounts for 43.00% of the total weight, CS / SH nanoparticles account for 2.23% of the total weight, glycerol accounts for 9.00% of the total weight, propylene glycol accounts for 3.50% of the total weight, xanthan gum accounts for 3.80% of the total weight, ethylparaben accounts for 0.20% of the total weight, and polysorbate 80 accounts for 15.12% of the total weight;

[0101] In the oil phase, sorbitan stearate 60 accounts for 1.68% of the total weight, glyceryl monostearate accounts for 0.71% of the total weight, cetyl alcohol accounts for 0.10% of the total weight, stearyl alcohol accounts for 0.16% of the total weight, and liquid paraffin accounts for 20.40% of the total weight.

[0102] The preparation process includes:

[0103] (1) Preparation of aqueous phase: Heat deionized water to 63°C, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, ethylparaben, and polysorbate 80 in sequence, and stir at 800 rpm to dissolve evenly to form an aqueous phase.

[0104] (2) Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 65°C and stir at 800 rpm to dissolve them uniformly to form an oil phase.

[0105] (3) Preparation of colostrum: At 57°C, slowly add the water phase to the stirring oil phase, and gradually increase the rotation speed from 500 to 800 rpm. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an O / W emulsion.

[0106] (4) Emulsification and homogenization: Emulsify at 50°C and 1500 rpm for 10 min. Lower the system temperature to 40-50°C, add 0.1% of the total weight of flavor, stir evenly at 600 rpm until dissolved, and cool to room temperature to obtain a nano-emulsion system.

[0107] Example 4

[0108] In this embodiment, the ratio is that the water phase accounts for 71.68% of the total weight of the emulsion, and the oil phase accounts for 28.22% of the total weight of the emulsion.

[0109] In the aqueous phase, deionized water accounts for 37.00% of the total weight, CS / SH nanoparticles account for 3.26% of the total weight, glycerol accounts for 8.00% of the total weight, propylene glycol accounts for 3.00% of the total weight, xanthan gum accounts for 4.20% of the total weight, ethylparaben accounts for 0.20% of the total weight, and polysorbate 80 accounts for 16.02% of the total weight;

[0110] In the oil phase, sorbitan stearate 60 accounts for 1.78% of the total weight, glyceryl monostearate accounts for 0.77% of the total weight, cetyl alcohol accounts for 0.11% of the total weight, stearyl alcohol accounts for 0.16% of the total weight, and liquid paraffin accounts for 25.40% of the total weight.

[0111] The preparation process includes:

[0112] (1) Preparation of aqueous phase: Heat deionized water to 65°C, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, ethylparaben, and polysorbate 80 in sequence, and stir at 650 rpm to uniformly dissolve to form an aqueous phase.

[0113] (2) Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 65°C and stir at 650 rpm to dissolve them uniformly to form an oil phase.

[0114] (3) Preparation of colostrum: At 59°C, slowly add the water phase to the stirring oil phase, and gradually increase the rotation speed from 500 to 800 rpm. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an O / W emulsion.

[0115] (4) Emulsification and homogenization: Emulsify at 50℃ and 1800 rpm for 13 min. Then reduce the system temperature to 40℃~50℃, add 0.1% of the total weight of flavor, stir at 600 rpm until dissolved, and cool to room temperature to obtain a nano-emulsion system.

[0116] Example 5

[0117] In this embodiment, the ratio is that the water phase accounts for 72.36% of the total weight of the emulsion, and the oil phase accounts for 27.54% of the total weight of the emulsion.

[0118] In the aqueous phase, deionized water accounts for 39.00% of the total weight, CS / SH nanoparticles account for 2.26% of the total weight, glycerol accounts for 8.00% of the total weight, propylene glycol accounts for 3.50% of the total weight, xanthan gum accounts for 4.10% of the total weight, ethylparaben accounts for 0.20% of the total weight, and polysorbate 80 accounts for 15.30% of the total weight;

[0119] In the oil phase, sorbitan stearate 60 accounts for 1.70% of the total weight, glyceryl monostearate accounts for 0.72% of the total weight, cetyl alcohol accounts for 0.09% of the total weight, stearyl alcohol accounts for 0.23% of the total weight, and liquid paraffin accounts for 24.80% of the total weight.

[0120] The preparation process includes:

[0121] (1) Preparation of aqueous phase: Heat deionized water to 61°C, add xanthan gum, CS / SH nanoparticles, glycerol, propylene glycol, ethylparaben, and polysorbate 80 in sequence, and stir at 750 rpm to evenly dissolve to form an aqueous phase.

[0122] (2) Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 68°C and stir at 750 rpm to dissolve them uniformly to form an oil phase.

[0123] (3) Preparation of colostrum: At 58°C, slowly add the water phase to the stirring oil phase, and gradually increase the rotation speed from 500 to 800 rpm. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an O / W emulsion.

[0124] (4) Emulsification and homogenization: Emulsify at 50℃ and 2500 rpm for 12 min. Then reduce the system temperature to 40℃~50℃, add 0.1% of the total weight of flavor, stir evenly at 600 rpm until dissolved, and cool to room temperature to obtain a nano-emulsion system.

[0125] Comparative Example 1

[0126] The difference from Example 1 is that sodium hyaluronate is used in the aqueous phase instead of CS / SH nanoparticles, and the added amount remains unchanged at 2.26% of the total weight.

[0127] Comparative Example 2

[0128] The difference from Example 1 is that the amount of CS / SH nanoparticles added is 0, and the amount of deionized water is changed to 42.37%.

[0129] Comparative Example 3

[0130] The difference from Example 1 is that the amount of CS / SH nanoparticles added is 0, the amount of deionized water is changed to 46.67%, the amount of sorbitan stearate 60 is changed to 9.81% of the total weight, the amount of polysorbate 80 is changed to 1.09% of the total weight, and the amount of liquid paraffin is changed to 24.20% of the total weight.

[0131] Test Example 1: Moisturizing performance test

[0132] The moisture content of the strings was measured using the differential method. At 25°C and 30% humidity, the moisture content of the strings was measured at 0, 6, 12, and 24 hours after application. The experimental results are shown in Table 1:

[0133] Table 1 Moisturizing performance test results

[0134]

[0135] Comparing the changes in string moisture content reveals that Example 1 significantly outperforms all comparative examples in moisturizing performance under low-humidity conditions. In particular, in Comparative Examples 2 and 3 (which lack sodium hyaluronate or CS / SH nanoparticles), the string moisture content after 24 hours is only approximately 50% of that in Example 1, demonstrating that the high hygroscopicity and sustained moisture-release properties of the CS / SH nanoparticles significantly enhance the long-lasting moisturizing ability of the emulsion. Furthermore, while the moisturizing performance of Comparative Example 1 (with sodium hyaluronate) is significantly improved compared to Comparative Examples 2 and 3, the duration of moisturizing is significantly reduced compared to Example 1. The present invention significantly enhances the moisturizing effect of the emulsion through the use of CS / SH nanoparticles and the optimization of the emulsification process, offering significant advantages.

[0136] Test Example 2: Particle Size Test

[0137] Emulsifier is an important factor affecting the size and uniformity of emulsion particles. Within a certain range, the more emulsifier is used, the better the emulsification effect and the smaller the particle size. Figure 1The particle size of the nanoemulsion was measured using a Malvern nanoparticle size and Zeta potential analyzer, as shown in Table 2 below:

[0138] Table 2 Particle size distribution test results

[0139]

[0140] The test results showed that the average particle size of the emulsion in Example 1 was 13.42 nm, with a distribution range concentrated between 3 and 100 nm, indicating a uniform particle size distribution. The total mass percentage of emulsifier in Comparative Examples 1, 2, and Example 1 was 16.8%, resulting in nanometer-sized emulsions. The total mass percentage of emulsifier in Comparative Example 3 was 10.9%, resulting in a micrometer-sized emulsion with a larger particle size.

[0141] Test Example 3: Stability Test

[0142] Stability test steps: (1) Add the emulsion to the centrifuge and adjust the speed to 3500 rpm for 10 min; (2) Place the emulsion sample in a constant temperature box at 40°C to simulate long-term storage conditions. Test the appearance and stratification of the sample after 30 days of storage. The results are shown in Table 3.

[0143] Table 3 Stability test results

[0144]

[0145] Stability testing results showed that Example 1, Comparative Examples 1, and 2 showed no delamination after centrifugation, while Comparative Example 3 exhibited slight delamination. After 30 days of storage at 40°C, Example 1, Comparative Examples 1, and 2 showed no delamination, color change, or odor change. Comparative Example 3 exhibited delamination, a slight color change, and a slight odor on the 28th day. This demonstrates that the present invention successfully addresses the issues of emulsion delamination and structural instability by optimizing the emulsification process. Furthermore, the addition of auxiliary ingredients such as antifreeze and preservatives significantly improves the storage safety of the emulsion.

[0146] Test Example 4: Penetration Test

[0147] Using the circular diffusion area method, take a standard qualitative filter paper with a flat, uncoated surface. Add 0.1 mL of the quantitative piano care lotion to the center of the paper and start a timer. Record the time it takes for the emulsion's diffusion radius to reach a steady state and measure the maximum diffusion diameter.

[0148] Calculation formula: , the results are shown in Table 4.

[0149] Table 4 Permeability test results

[0150]

[0151] The penetration test results show that the penetration rates of Example 1, Comparative Examples 1, and 2 are similar, but the penetration rate of Comparative Example 3 is significantly lower. This also means that the nanoemulsion of the present invention has good permeability, which can quickly penetrate the outer nylon layer into the inner metal string, providing long-term noise reduction and enhancing the warmth of the sound.

Claims

1. A nanoemulsion for guitar string maintenance, comprising an aqueous phase and an oil phase, characterized in that: Calculated as a percentage of the total mass of the nanoemulsion: The aqueous phase comprises: 35% to 45% water, 3% to 5% xanthan gum, 1.5% to 3.5% chitosan / sodium hyaluronate nanoparticles, 5% to 15% glycerol, 2% to 5% propylene glycol, 0.1% to 0.5% ethylparaben, and 15% to 25% polysorbate 80; The oil phase comprises: sorbitan stearate 600%-6%, glyceryl monostearate 0.4%-2%, cetyl alcohol 0.05%-0.8%, stearyl alcohol 0.05%-0.5%, and liquid paraffin 15%-25.4%.

2. The string maintenance nanoemulsion according to claim 1, characterized in that Calculated as a percentage of the total mass of the nanoemulsion, the water phase accounts for 65% to 75% and the oil phase accounts for 25% to 35%.

3. The string maintenance nanoemulsion according to claim 1, characterized in that The total mass percentage of polysorbate 80 and sorbitan stearate 60 is between 15% and 28%.

4. The string maintenance nanoemulsion according to claim 1, characterized in that The chitosan / sodium hyaluronate nanoparticles are prepared by an ion gel method using chitosan as a carrier material and sodium tripolyphosphate (TPP) as a cross-linking agent.

5. The string maintenance nanoemulsion according to claim 4, characterized in that Chitosan / sodium hyaluronate nanoparticles were prepared as follows: A sodium hyaluronate aqueous solution and a chitosan glacial acetic acid solution are mixed together, and a TPP aqueous solution is added dropwise under stirring conditions. The reaction is carried out at 30°C to 40°C. The mass percentage of sodium hyaluronate to the mass of chitosan is 3% to 8%, and the mass ratio of chitosan to TPP is (5-7):

1. After the reaction is completed, insoluble impurities are removed by filtration, and unreacted small molecules are removed by dialysis to obtain chitosan / sodium hyaluronate nanoparticles. The concentration of the TPP aqueous solution is 0.5 mg / mL ~1.0 mg / mL, and the chitosan glacial acetic acid solution is chitosan dissolved in a glacial acetic acid solution with a pH of 4 and a mass fraction of 1%, and the concentration of the chitosan glacial acetic acid solution is 1.5 mg / mL ~2.5 mg / mL.

6. The string maintenance nanoemulsion according to any one of claims 1 to 5, characterized in that: Calculated as a percentage of the total mass of the nanoemulsion, the string maintenance nanoemulsion also includes 0.05% to 0.2% of essence.

7. A method for preparing the string maintenance nanoemulsion according to any one of claims 1 to 5, characterized in that: The following steps are involved: Preparation of aqueous phase: Heat water to 55°C-60°C, add xanthan gum, chitosan / sodium hyaluronate nanoparticles, glycerin, propylene glycol, ethylparaben, and polysorbate 80 in sequence, stir and dissolve evenly to form an aqueous phase; Preparation of oil phase: Heat sorbitan stearate 60, glyceryl monostearate, cetyl alcohol, stearyl alcohol, and liquid paraffin to 60°C~65°C, stir and dissolve evenly to form an oil phase; Colostrum preparation: Add the water phase to the oil phase under stirring at 60℃~65℃. When the mass of the water phase is greater than that of the oil phase, a phase inversion occurs to form an oil-in-water emulsion. Emulsification and homogenization: After the system temperature drops to 40°C~50°C, intermittent emulsification is carried out, and after intermittent emulsification, it is cooled to room temperature to obtain the guitar string maintenance nanoemulsion.

8. The method for preparing the string maintenance nanoemulsion according to claim 7, wherein: During the colostrum preparation process, the aqueous phase is added to the oil phase at a rate of 1 mL / s to 2 mL / s, the stirring speed is controlled at 500 rpm to 800 rpm, and the emulsification time is controlled at 10 min to 15 min.

9. The method for preparing the string maintenance nanoemulsion according to claim 7, wherein: During the emulsification and homogenization process, the system temperature dropped to 40℃~50℃, then the essence was added and intermittent emulsification was performed.

10. The method for preparing the string maintenance nanoemulsion according to claim 7, characterized in that: The rotation speed of intermittent emulsification is 1500 rpm ~2500 rpm, the emulsification time is 5 min ~10 min, and the cooling rate after intermittent emulsification is 3℃ ~5℃ per minute.

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