Self-emulsifying amino silicone oil emulsion and preparation method thereof

Abstract

The invention relates to the technical field of wash supplies, in particular to a self-emulsifying amino silicone oil emulsion and a preparation method thereof. The anti-rust silicone oil is prepared from the following raw materials: amino modified silicone oil, PEG-7 glyceryl cocoate, a polyether block copolymer, organic acid, a preservative and deionized water, the mass ratio of the amino modified silicone oil to the PEG-7 glyceryl cocoate is (2-9): 1. According to the invention, through molecular collaborative design of amino modified silicone oil and PEG-7 glyceryl cocoate and in combination with gradient polymerization and self-assembly regulation and control technologies, the whole process optimization from molecular structure design to precise control of the particle size of the emulsion is realized, and the stability, self-emulsifying efficiency and conditioning performance of the emulsion are remarkably improved; the self-emulsifying amino silicon oil emulsion meeting the requirements of mild nursing and green consumption is prepared.

Description

Technical Field

[0001] This invention relates to the field of personal care products technology, and more specifically, to a self-emulsifying amino silicone oil emulsion and its preparation method. Background Technology

[0002] In the personal care and household cleaning industries, amino silicone oil emulsions are a commonly used core conditioning ingredient that enhances the softness and smoothness of washing and care products. While self-emulsification technology simplifies the preparation process, existing technologies still have significant drawbacks: First, traditional bulk emulsification requires the synthesis of crude silicone oil, which is then mixed with a large amount of emulsifier using energy-intensive equipment. This process is lengthy, inefficient, and results in inconsistent particle size between batches. Second, maintaining emulsion stability necessitates the use of a significant amount of emulsifier, increasing costs and potentially causing skin and environmental irritation, thus failing to meet market demand for gentle, eco-friendly products. Third, existing emulsions generally have low solids content, making it difficult to achieve high concentrations exceeding 30%, leading to high transportation costs and limited formulation options. Furthermore, they exhibit poor storage stability, prone to issues such as separation and oil drift.

[0003] In summary, existing amino silicone oil emulsions have significant shortcomings in terms of preparation efficiency, emulsifier dosage, and product stability. Summary of the Invention

[0004] The purpose of this invention is to solve the comprehensive defects of existing amino silicone oil emulsions in terms of preparation efficiency, emulsifier dosage and stability, and to achieve a synergistic unity of high efficiency and stability.

[0005] The purpose of this invention is to provide a self-emulsifying amino silicone oil emulsion and its preparation method. Through the molecular synergistic design of amino-modified silicone oil and PEG-7 glycerol cocoate, combined with gradient polymerization and self-assembly control technology, the entire process optimization from molecular structure design to precise control of emulsion particle size is achieved, which significantly improves the stability, self-emulsification efficiency and conditioning properties of the emulsion.

[0006] To achieve the above objectives, one objective of this invention is to provide a self-emulsifying amino silicone oil emulsion, comprising the following raw materials in the indicated mass percentages: The composition consists of 20-40% amino-modified silicone oil, 5-20% PEG-7 glyceryl cocoate, 5-15% polyether block copolymer, 0.1-0.5% organic acid, 0.3-0.8% preservative, and the balance being deionized water. The mass ratio of the amino-modified silicone oil to PEG-7 glyceryl cocoate is 2-9:1. The amino-modified silicone oil is a ternary copolymer block polysiloxane, prepared by polymerization reaction from the following raw materials in the indicated mass proportions: 5-15% γ-piperazinylpropylmethyldimethoxysilane, 1-3% hexamethyldisiloxane, 0.5-1% basic catalyst, with the balance being octamethylcyclotetrasiloxane; The PEG-7 glyceryl cocoate is obtained by esterification of the following raw materials in the indicated mass percentages: Coconut oil acid 30-40%, composite catalyst 0.3-0.8%, balance glycerol polyoxyethylene ether-7; The composite catalyst is composed of p-toluenesulfonic acid and phosphorous acid in a mass ratio of 2:1.

[0007] A second objective of this invention is to provide a method for preparing the aforementioned self-emulsifying amino silicone oil emulsion, comprising the following steps: Step S1: First, weigh the raw materials according to their mass percentage; Step S2: Mix amino-modified silicone oil with PEG-7 glyceryl cocoate, add polyether block copolymer and deionized water, and stir to form a self-emulsifying pre-dispersion; Step S3: Add organic acid to the self-emulsifying pre-dispersion to adjust the pH to 6.0-7.0, and then transfer the system to a homogenizer to refine the emulsion particle size to below 150nm; Step S4: Transfer the homogenized emulsion to a mixing tank and stir at room temperature for 2-4 hours for stabilization; finally, add preservatives, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

[0008] As a further improvement to this technical solution, in step S1, octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane and alkaline catalyst are added to the reaction vessel, and the temperature is raised to 80-90℃ under nitrogen protection, and the reaction is carried out for 1-2 hours to perform ring-opening polymerization. The temperature was then raised to 100-110℃ and the reaction continued for 6-8 hours to complete chain growth. Finally, the temperature was raised to 130-140℃ under vacuum conditions of ≤-0.095 MPa to remove low molecular weight substances for 1 hour. The product was then cooled and discharged to obtain amino-modified silicone oil.

[0009] As a further improvement to this technical solution, in step S1, glycerol polyoxyethylene ether-7 and coconut oil acid are added to a reaction vessel, along with a composite catalyst and an azeotropic solvent. Heat to 165-175℃ and perform an azeotropic dehydration reaction for 4-6 hours until the theoretical water yield reaches over 95%. After the reaction was completed, the temperature was raised to 120-130℃ under a vacuum of ≤-0.095 MPa, and the azeotropic solvent was recovered by vacuum distillation. Cool to 80-90℃, add a neutralizing agent to adjust the pH to 6.0-7.0, add activated clay or activated carbon and stir to adsorb for 30 minutes, then filter to obtain PEG-7 glycerol cocoate.

[0010] As a further improvement to this technical solution, in step S2, the mixture is stirred at 40-60℃ for 30-60 minutes to form a self-emulsifying pre-dispersion.

[0011] As a further improvement to this technical solution, in step S3, the system is homogenized in a homogenizer at 5000-8000 rpm for 10-20 min.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: In this self-emulsifying amino silicone oil emulsion and its preparation method, the amino-modified silicone oil first incorporates polyether segments directly into the polysiloxane backbone through a gradient polymerization reaction, achieving intrinsic hydrophilic modification at the molecular level. This lays the structural foundation for the subsequent self-emulsification process without the need for external emulsifiers. PEG-7 glyceryl cocoate is refined through composite catalysis and azeotropic dehydration technology. Its high purity and excellent hydrophilic-lipophilic balance provide an ideal solubilizing environment for constructing a stable emulsion system. Subsequently, under the synergistic effect of low-temperature stirring and pH-responsive regulation, amino-modified silicone oil and PEG-7 glyceryl cocoate form a self-emulsifying pre-dispersion. The pH is precisely adjusted to 6.0-7.0 by organic acid to protonate the amino groups, inducing molecular chain rearrangement and interfacial self-assembly. After homogenization and refinement, the emulsion particle size is controlled below 150 nm, achieving uniform and stable nanoscale emulsion. Finally, stabilization treatment is carried out by slow stirring at room temperature to fully relax the intermolecular interactions, transforming the self-emulsifying properties of the molecular design into a nanoemulsion system with uniform particle size, long-term stability, and excellent transparency. This fundamentally overcomes the technical defects of traditional processes, such as low preparation efficiency, poor batch stability, and skin irritation caused by reliance on high-energy emulsification and large amounts of emulsifiers. A self-emulsifying amino silicone oil emulsion that meets the needs of gentle care and green consumption has been successfully prepared. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2 This is a schematic diagram of the yellowing index of each group in the test examples of this invention; Figure 3 This is a schematic diagram of the hydrophilicity time for each group in the experimental examples of this invention. Detailed Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] In the personal care and household cleaning industries, amino silicone oil emulsions are widely used as a core conditioning ingredient in shampoos, conditioners, shower gels, and laundry detergents due to their excellent softness and smoothness. Amino silicone oil emulsions prepared using self-emulsification technology can spontaneously form a stable system using the hydrophilic groups in their molecular structure without the need for external high-energy emulsification equipment, effectively enhancing the product's adhesion and lubrication on hair and fabric surfaces.

[0016] However, existing amino silicone oil emulsions still have significant shortcomings in terms of preparation process and performance control.

[0017] First, traditional emulsion preparation often employs bulk emulsification, which requires the pre-synthesization of high-viscosity silicone crude oil, followed by compounding with a large amount of emulsifier using high-speed shearing or homogenization equipment. This process is lengthy and energy-intensive. Since bulk emulsification relies on external mechanical force to achieve oil-water dispersion, its production efficiency is limited, and batch-to-batch differences in particle size distribution are difficult to avoid, resulting in inconsistent product consistency and stability.

[0018] Secondly, to maintain emulsion stability, bulk emulsification typically requires a higher proportion of emulsifiers (such as nonionic surfactants), which not only increases formulation costs but may also cause irritation and burden on the scalp, skin, or environment due to surfactant residue. Especially with the consumer trend advocating gentle and green skincare, traditional processes using high amounts of emulsifiers can no longer meet the market's demand for low-irritant and highly safe products.

[0019] In summary, existing amino silicone oil emulsions have significant shortcomings in terms of preparation efficiency, emulsifier dosage, and product stability.

[0020] Therefore, one of the objectives of this invention is to provide a self-emulsifying amino silicone oil emulsion and its preparation method, comprising the following raw materials in the indicated mass percentages: The composition consists of 20-40% amino-modified silicone oil, 5-20% PEG-7 glyceryl cocoate, 5-15% polyether block copolymer, 0.1-0.5% organic acid, 0.3-0.8% preservative, and the balance being deionized water. The mass ratio of amino-modified silicone oil to PEG-7 glyceryl cocoate is 2-9:1. Amino-modified silicone oil is a ternary copolymer block polysiloxane, prepared by polymerization reaction from the following raw materials in the indicated mass proportions: 5-15% γ-piperazinylpropylmethyldimethoxysilane, 1-3% hexamethyldisiloxane, 0.5-1% basic catalyst, with the balance being octamethylcyclotetrasiloxane; PEG-7 glyceryl cocoate is prepared by esterification of the following raw materials in the indicated mass percentages: Coconut oil acid 30-40%, composite catalyst 0.3-0.8%, balance glycerol polyoxyethylene ether-7; The composite catalyst is composed of p-toluenesulfonic acid and phosphorous acid in a mass ratio of 2:1.

[0021] In amino-modified silicone oils, siloxane segments serve as the main backbone, imparting excellent softness and a smooth feel; polyether segments are embedded in the molecular backbone, providing hydrophilicity and self-emulsifying capabilities; polyamine segments are introduced using γ-piperazinylpropylmethyldimethoxysilane to enhance adsorption performance and inhibit yellowing. Polyether block copolymers, acting as auxiliary self-emulsifiers, synergistically optimize the dispersibility and stability of the emulsion with amino-modified silicone oils. PEG-7 glyceryl cocoate possesses excellent hydrophilic-lipophilic balance, both solubilizing oils and synergistically constructing stable multi-emulsion systems with amino silicone oils. Organic acids adjust the system pH to 6.0-7.0, protonating the amino groups and enhancing emulsion stability. Preservatives ensure product shelf-life quality.

[0022] Please see Figure 1 As shown, a second objective of this invention is to provide a method for preparing the aforementioned self-emulsifying amino silicone oil emulsion, comprising the following steps: Step S1: First, weigh the raw materials according to their mass percentage.

[0023] The synthesis method of the amino-modified silicone oil in this invention is as follows: Octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane, and an alkaline catalyst were added to a reactor in a set ratio. Under nitrogen protection, the temperature was raised to 80-90℃ and reacted for 1-2 hours to carry out ring-opening polymerization. Then, the temperature was raised to 100-110℃ and the reaction was continued for 6-8 hours to complete chain growth. Finally, under a vacuum of ≤-0.095 MPa, the temperature was raised to 130-140℃ to remove low molecular weight substances for 1 hour. The product was then cooled and discharged to obtain amino-modified silicone oil.

[0024] In this invention, the synthesis process of PEG-7 glyceryl cocoate is as follows: Glyceryl polyoxyethylene ether-7 and coconut oil acid were added to a reactor, along with a composite catalyst and an azeotropic solvent (cyclohexane or toluene). The temperature was raised to 165-175℃, and the azeotropic dehydration reaction was carried out for 4-6 hours until the theoretical water yield reached more than 95%. After the reaction was completed, the temperature was raised to 120-130℃ under a vacuum of ≤-0.095 MPa, and the azeotropic solvent was recovered by vacuum distillation. The temperature was lowered to 80-90℃, and a neutralizing agent was added to adjust the pH to 6.0-7.0. Activated clay or activated carbon was added and stirred for adsorption for 30 minutes. The mixture was then filtered to obtain PEG-7 glyceryl coconut oil ester.

[0025] Step S2: Mix the amino-modified silicone oil obtained in step S1 with PEG-7 glycerol cocoate at a mass ratio of 2-9:1, add polyether block copolymer and deionized water, and stir at 40-60℃ for 30-60 min to form a self-emulsifying pre-dispersion. Step S3: Slowly add organic acid to the self-emulsifying pre-dispersion in step S2 above to adjust the pH to 6.0-7.0, then transfer the system to a homogenizer and homogenize at 5000-8000 rpm for 10-20 min to refine the emulsion particle size to below 150 nm. Step S4: Transfer the homogenized emulsion to a mixing tank and slowly stir at room temperature for 2-4 hours for stabilization treatment; finally, add preservatives, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

[0026] In this invention, the intrinsic self-emulsifying ability of amino silicone oil is achieved by directly embedding polyether segments into the polysiloxane backbone in a block copolymer design, completely eliminating the need for external emulsifiers. Simultaneously, high-purity PEG-7 glycerol cocoate is prepared using composite catalysis and azeotropic dehydration technology. The two work synergistically in the formulation—the solubilizing and emulsifying ability of PEG-7 glycerol cocoate provides an ideal environment for the uniform dispersion of amino silicone oil, while the nanoscale conditioning effect of amino silicone oil imparts excellent smoothness. In the preparation process, high-quality intermediates are first obtained through gradient polymerization and azeotropic dehydration, followed by self-assembly regulation and pH-responsive stabilization technology to finally form a nanoemulsion with uniform particle size and excellent stability. This emulsion can hold 8-10% oil in transparent formulations while remaining clear, and can construct a stable water-in-oil-in-water structure in multi-emulsion systems, significantly improving the overall performance of washing and care products.

[0027] The following specific embodiments further illustrate the self-emulsifying amino silicone oil emulsion and its preparation method provided by the present invention.

[0028] Example 1 Step S1: First, weigh out the following ingredients according to their mass percentages: 20% amino-modified silicone oil, 5% PEG-7 glyceryl cocoate, 5% polyether block copolymer, 0.5% organic acid, 0.3% preservative, and the remainder is deionized water.

[0029] Among them, the amino-modified silicone oil is a ternary copolymer block structure polysiloxane, which is obtained by polymerization reaction from raw materials in the following mass proportions: 15% γ-piperazinylpropylmethyldimethoxysilane, 1% hexamethyldisiloxane, 1% basic catalyst, with the balance being octamethylcyclotetrasiloxane; PEG-7 glyceryl cocoate is prepared by esterification of the following raw materials in the indicated mass percentages: 30% coconut oil acid, 0.8% composite catalyst, and the balance is glycerol polyoxyethylene ether-7.

[0030] Specifically, the synthesis method of the amino-modified silicone oil in this invention is as follows: Octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane, and an alkaline catalyst were added to a reactor in a set ratio. The mixture was heated to 80°C under nitrogen protection and reacted for 2 hours to carry out ring-opening polymerization. Then, the temperature was raised to 100°C and the reaction was continued for 8 hours to complete chain growth. Finally, the mixture was heated to 130°C under a vacuum of ≤-0.095 MPa to remove low molecular weight substances for 1 hour. The mixture was then cooled and discharged to obtain amino-modified silicone oil.

[0031] The synthesis process of PEG-7 glyceryl cocoate is as follows: Glyceryl polyoxyethylene ether-7 and coconut oil acid were added to a reactor, along with a composite catalyst and an azeotropic solvent (cyclohexane). The temperature was raised to 165°C, and the azeotropic dehydration reaction was carried out for 6 hours until the theoretical water yield reached more than 95%. After the reaction was completed, the temperature was raised to 120°C under a vacuum of ≤-0.095 MPa, and the azeotropic solvent was recovered by vacuum distillation. The temperature was lowered to 90°C, a neutralizing agent was added to adjust the pH to 6.0, activated clay was added and stirred for adsorption for 30 minutes, and then filtered to obtain PEG-7 glyceryl cocoate.

[0032] Step S2: Mix the amino-modified silicone oil obtained in step S1 with PEG-7 glycerol cocoate at a mass ratio of 4:1, add polyether block copolymer and deionized water, and stir at 60°C for 30 min to form a self-emulsifying pre-dispersion. Step S3: Slowly add organic acid to the self-emulsifying pre-dispersion in step S2 above to adjust the pH to 7.0, then transfer the system to a homogenizer and homogenize at 5000 rpm for 20 min to refine the emulsion particle size to below 150 nm. Step S4: Transfer the homogenized emulsion to a mixing tank and slowly stir at room temperature for 2 hours for stabilization treatment; finally, add preservative, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

[0033] Example 2 Step S1: First, weigh out the following ingredients according to their mass percentages: 30% amino-modified silicone oil, 10% PEG-7 glycerol cocoate, 10% polyether block copolymer, 0.2% organic acid, 0.5% preservative, and the remainder is deionized water.

[0034] Among them, the amino-modified silicone oil is a ternary copolymer block structure polysiloxane, which is obtained by polymerization reaction from raw materials in the following mass proportions: 10% γ-piperazinylpropylmethyldimethoxysilane, 2% hexamethyldisiloxane, 0.8% basic catalyst, and the balance being octamethylcyclotetrasiloxane; PEG-7 glyceryl cocoate is prepared by esterification of the following raw materials in the indicated mass percentages: 35% coconut oil acid, 0.5% composite catalyst, and the balance is glycerol polyoxyethylene ether-7.

[0035] Specifically, the synthesis method of the amino-modified silicone oil in this invention is as follows: Octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane, and an alkaline catalyst were added to a reactor in a set ratio. The mixture was heated to 85°C under nitrogen protection and reacted for 1 hour to carry out ring-opening polymerization. Then, the temperature was raised to 105°C and the reaction was continued for 7 hours to complete chain growth. Finally, the mixture was heated to 135°C under a vacuum of ≤-0.095 MPa to remove low molecular weight substances for 1 hour. The mixture was then cooled and discharged to obtain amino-modified silicone oil.

[0036] The synthesis process of PEG-7 glyceryl cocoate is as follows: Glyceryl polyoxyethylene ether-7 and coconut oil acid were added to a reactor, along with a composite catalyst and an azeotropic solvent (toluene). The temperature was raised to 170°C, and the azeotropic dehydration reaction was carried out for 5 hours until the theoretical water yield reached more than 95%. After the reaction was completed, the temperature was raised to 125°C under a vacuum of ≤-0.095MPa, and the azeotropic solvent was recovered by vacuum distillation. The temperature was lowered to 85°C, a neutralizing agent was added to adjust the pH to 7.0, activated clay was added and stirred for adsorption for 30 minutes, and then filtered to obtain PEG-7 glyceryl cocoate.

[0037] Step S2: Mix the amino-modified silicone oil obtained in step S1 with PEG-7 glycerol cocoate at a mass ratio of 3:1, add polyether block copolymer and deionized water, and stir at 50°C for 40 min to form a self-emulsifying pre-dispersion. Step S3: Slowly add organic acid to the self-emulsifying pre-dispersion in step S2 above to adjust the pH to 6.0, then transfer the system to a homogenizer and homogenize at 7000 rpm for 15 min to refine the emulsion particle size to below 150 nm. Step S4: Transfer the homogenized emulsion to a mixing tank and slowly stir at room temperature for 3 hours for stabilization treatment; finally, add preservatives, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

[0038] Example 3 Step S1: First, weigh out the following components by mass percentage: 40% amino-modified silicone oil, 20% PEG-7 glyceryl cocoate, 15% polyether block copolymer, 0.1% organic acid, 0.8% preservative, and the remainder is deionized water.

[0039] Among them, the amino-modified silicone oil is a ternary copolymer block structure polysiloxane, which is obtained by polymerization reaction from raw materials in the following mass proportions: 5% γ-piperazinylpropylmethyldimethoxysilane, 3% hexamethyldisiloxane, 0.5% basic catalyst, with the balance being octamethylcyclotetrasiloxane; PEG-7 glyceryl cocoate is prepared by esterification of the following raw materials in the indicated mass percentages: 40% coconut oil acid, 0.3% composite catalyst, and the balance is glycerol polyoxyethylene ether-7.

[0040] Specifically, the synthesis method of the amino-modified silicone oil in this invention is as follows: Octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane, and an alkaline catalyst were added to a reactor in a set ratio. The mixture was heated to 90°C under nitrogen protection and reacted for 1 hour to carry out ring-opening polymerization. Then, the temperature was raised to 110°C and the reaction was continued for 6 hours to complete chain growth. Finally, the mixture was heated to 140°C under a vacuum of ≤-0.095 MPa to remove low molecular weight substances for 1 hour. The mixture was then cooled and discharged to obtain amino-modified silicone oil.

[0041] The synthesis process of PEG-7 glyceryl cocoate is as follows: Glyceryl polyoxyethylene ether-7 and coconut oil acid were added to a reactor, along with a composite catalyst and an azeotropic solvent (toluene). The temperature was raised to 175°C, and the azeotropic dehydration reaction was carried out for 4 hours until the theoretical water yield reached more than 95%. After the reaction was completed, the temperature was raised to 130°C under a vacuum of ≤-0.095MPa, and the azeotropic solvent was recovered by vacuum distillation. The temperature was lowered to 80°C, a neutralizing agent was added to adjust the pH to 7.0, activated carbon was added, and the mixture was stirred and adsorbed for 30 minutes. The mixture was then filtered to obtain PEG-7 glyceryl coconut oil ester.

[0042] Step S2: Mix the amino-modified silicone oil obtained in step S1 with PEG-7 glycerol cocoate at a mass ratio of 2:1, add polyether block copolymer and deionized water, and stir at 40°C for 60 min to form a self-emulsifying pre-dispersion. Step S3: Slowly add organic acid to the self-emulsifying pre-dispersion in step S2 above to adjust the pH to 6.0, and then transfer the system to a homogenizer and homogenize at 8000 rpm for 10 min to refine the emulsion particle size to below 150 nm. Step S4: Transfer the homogenized emulsion to a mixing tank and slowly stir at room temperature for 4 hours for stabilization treatment; finally, add preservatives, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

[0043] The self-emulsifying amino silicone oil emulsions prepared according to Examples 1-3 were then systematically tested for their physicochemical properties, stability, and application performance.

[0044] Physicochemical performance testing: Based on industry standard HG / T 4439-2012 "Textile Dyeing and Finishing Auxiliaries Polyether Block Amino Silicone Oil Emulsion" and general test methods for cosmetic emulsions, the appearance, pH value, solid content, particle size and zeta potential of the emulsion were characterized.

[0045] Stability testing includes centrifugal stability, dilution stability, heat resistance stability, cold resistance stability, and acid and alkali resistance stability tests to evaluate the storage and use stability of the emulsion under different conditions.

[0046] Application performance testing: Based on HG / T 4917-2016 "Determination of hydrophilicity of amino silicone oil softener in textile dyeing and finishing auxiliaries" and HG / T 4734-2014 "Determination of yellowing properties of amino silicone oil softener in textile dyeing and finishing auxiliaries", the softness, hydrophilicity and anti-yellowing properties of hair or fabrics after emulsion treatment are evaluated.

[0047] Sample preparation The self-emulsifying amino silicone oil emulsions prepared in Examples 1-3 were allowed to stand and defoam before being used directly as test samples. At least three parallel samples were prepared for each example. For application performance testing, the emulsion was formulated into a working solution with a solid content of 0.5%, and white cotton cloth or standardized hair bundles were treated by impregnation at a liquor ratio of 1:20, a treatment temperature of 40°C, and a time of 20 minutes. After that, the emulsions were dehydrated and dried for later use.

[0048] Test environment and equipment The physicochemical properties tests were conducted in a constant temperature and humidity laboratory at (23±2)℃ and (50±5)% relative humidity. The main equipment included: Malvern Zetasizer Nano ZSP Particle Size Analyzer: Used to determine the average particle size and Zeta potential of emulsions, with a measurement range of 0.3 nm to 10 μm; Mettler FE28 pH meter: resolution 0.01 pH, used for measuring the pH value of emulsions; Shimadzu UV-2600i UV spectrophotometer: used for determining the transmittance of emulsions; Xiangyi H1850 centrifuge: used for centrifugal stability testing; Electric thermostatic incubator and low-temperature freezer: used for heat and cold resistance stability testing; ZBD type whiteness meter: used to measure the whiteness change of treated fabrics and evaluate yellowing performance; Standard capillary water absorption time tester: used to determine hydrophilic properties; Test Procedures and Data Processing 1. Appearance and physicochemical properties testing a) Appearance: Take an appropriate amount of emulsion and place it in a 20mL colorless transparent glass bottle. Observe the color, state and transparency under natural light.

[0049] b) pH value determination: Take 50 mL of emulsion and measure it directly with a calibrated pH meter according to the method of GB / T 8325-2012 "Determination of pH value of surfactants". Repeat 3 times and take the average value.

[0050] c) Determination of solid content: Accurately weigh 2.0 g of emulsion sample (accurate to 0.0001 g), place it in a constant temperature oven at 105℃ and dry it for 3 h until constant weight. Calculate the solid content according to the formula, and take the average value of 3 parallel determinations.

[0051] d) Particle size and Zeta potential determination: Take an appropriate amount of emulsion, dilute it with deionized water to an appropriate concentration (to avoid multiple scattering), pour it into a polystyrene cuvette, place it in a particle size analyzer, and measure the average particle size (Z-Average) and polydispersity index (PDI) after equilibration at 25℃ for 2 min; measure the Zeta potential using a dedicated potential cell. Each sample was measured three times and the average value was taken. The results are recorded in Table 1.

[0052] Table 1. Appearance and physicochemical properties of self-emulsifying amino silicone oil emulsions in Examples 1-3 2. Stability testing a) Centrifugal stability: Place 10 mL of the emulsion in a centrifuge tube and centrifuge at 3000 r / min for 30 min. After centrifugation, visually inspect for layering, oil floating, or precipitation. Evaluation criteria: No layering or oil floating indicates a satisfactory result.

[0053] b) Dilution stability: The emulsion was diluted with deionized water to 1 / 2, 1 / 5, and 1 / 10 of its original solid content, respectively. After standing for 24 hours, the presence of stratification or flocculation was observed. Simultaneously, changes in particle size and transmittance before and after dilution were measured.

[0054] c) Heat resistance stability: Take 50 mL of emulsion and put it into a 100 mL stoppered glass bottle. After sealing, place it in a constant temperature incubator at (50±2) ℃. After standing for 48 h, take it out and restore it to room temperature. Observe whether it separates into layers or flocculates, and compare the particle size and appearance changes with the initial sample.

[0055] d) Cold resistance stability: Take 50 mL of emulsion and put it into a 100 mL glass bottle with a stopper. After sealing, put it in a refrigerator at (-5±2)℃ and let it stand for 48 h. After restoring to room temperature, observe whether it separates into layers or flocculates, and compare the changes in particle size and appearance with the initial sample.

[0056] e) Acid and alkali resistance: The pH of the emulsion was adjusted to 4.0, 8.0, and 10.0 respectively using glacial acetic acid or 10% NaOH solution. After standing for 24 hours, the emulsion was observed to see if it separated into layers, flocculated, or precipitated. The results are recorded in Table 2.

[0057] Table 2. Stability of self-emulsifying amino silicone oil emulsions in Examples 1-3 3. Application performance testing a) Softness evaluation: A multi-person hand touch assessment method was used. Five trained evaluators were selected to conduct blind tests and score the cotton fabric or hair bundles treated with emulsion, on a scale of 1 to 5 (1 being poor softness and 5 being good softness). The average value was taken as the final result.

[0058] b) Hydrophilicity test: According to HG / T 4917-2016 standard, the capillary water absorption time method was used. The cotton fabric sample, after being treated with emulsion and conditioned, was laid flat. A drop of distilled water (approximately 0.05 mL) was dropped 1 cm above the fabric surface. The time required for the water droplet to be completely absorbed by the fabric was recorded using a stopwatch. Ten different locations were measured for each sample, and the average value was taken. The shorter the time, the better the hydrophilicity.

[0059] c) Yellowing performance test: The whiteness was measured using a whiteness meter according to HG / T 4734-2014 standard. The whiteness value W1 of the untreated blank cotton fabric and the whiteness value W2 of the cotton fabric treated with emulsion were measured separately. The yellowing index ΔW = W1 - W2 was calculated using the formula. The smaller the ΔW value, the better the anti-yellowing performance.

[0060] d) Transmittance determination: Take the emulsion stock solution, dilute it with deionized water to a solid content of 1.0%, and pour it into a 1 cm quartz cuvette. Using deionized water as a reference, measure the transmittance at a wavelength of 500 nm. Repeat the measurement three times and take the average value. The results are recorded in Table 3.

[0061] Table 3 Application performance of self-emulsifying amino silicone oil emulsions in Examples 1-3 According to Table 1-3, The self-emulsifying amino silicone oil emulsions prepared in Examples 1-3 are all stable emulsion systems with a semi-transparent bluish tint. The average particle size is controlled at around 100 nm, far below the design target of 150 nm. The Zeta potential is above +35 mV, indicating excellent electrostatic stability. No stratification, oil drift, or flocculation was observed in centrifugal stability, heat and cold resistance, and acid and alkali resistance tests, indicating good storage stability. In terms of application performance, the softness rating is above 4.7, the hydrophilicity time is below 4 s, and the yellowing index is below 2.5%, significantly better than traditional amino silicone oil emulsions. This demonstrates that the method provided by this invention can yield self-emulsifying amino silicone oil emulsions with controllable particle size, excellent stability, and superior application performance, fully meeting the requirements for gentleness and efficient conditioning performance in personal care and household cleaning fields.

[0062] Test case To verify that the key to achieving low yellowing, high oil carrying capacity, and excellent stability in the self-emulsifying amino silicone oil emulsion of this invention lies in the polyamine segment structure introduced by γ-piperazinylpropylmethyldimethoxysilane, the synergistic system of the specific mass ratio (2-9:1) of amino-modified silicone oil and PEG-7 glycerol cocoate, and the core role of the composite catalyst and azeotropic dehydration technology in preparing high-purity PEG-7 glycerol cocoate, this experimental example, based on the formulation and process of Example 2, systematically changes the core technical features and designs the following five sets of comparative experiments: Control group E1: Conventional amino-modified group Solution: A conventional aminoethylaminopropyl dimethoxysilane was used to replace γ-piperazinylpropylmethyldimethoxysilane as the aminosilane coupling agent. The remaining monomer ratios and polymerization process were the same as in Example 2, resulting in a comparative amino-modified silicone oil. Then, an emulsion was prepared according to the formulation and process of Example 2 (30% amino-modified silicone oil, 10% PEG-7 glycerol cocoate, 10% polyether block copolymer, 0.2% organic acid, 0.5% preservative, and the balance deionized water).

[0063] Objective: To establish a performance benchmark and verify the performance of amino silicone oils prepared solely using conventional aminosilanes without employing a γ-piperazine structure in terms of yellowing properties, adsorption properties, and emulsion stability.

[0064] Control group E2: Proportion deviation group Solution: Keep all raw material types and preparation processes unchanged in Example 2, only change the mass ratio of amino-modified silicone oil to PEG-7 glycerol cocoate to 1:1 (i.e., 20% amino-modified silicone oil, 20% PEG-7 glycerol cocoate, with the total oil phase ratio remaining unchanged).

[0065] Objective: To isolate and verify the changes in the self-emulsification effect, particle size distribution, and stability of emulsions when the mass ratio of amino silicone oil to PEG-7 glyceryl cocoate deviates from the range (2-9:1) defined in this invention.

[0066] Control group E3: Conventional esterified PEG-7 glycerol cocoate group Solution: PEG-7 glycerol cocoate was prepared using a conventional esterification process, specifically using only p-toluenesulfonic acid as a single catalyst (0.5%), without adding phosphorous acid for compounding, and without azeotropic dehydration or activated clay adsorption purification. The preparation processes for the remaining amino-modified silicone oil (using a γ-piperazine structure) and emulsion were the same as in Example 2.

[0067] Objective: To isolate and verify the effect of high-purity PEG-7 glyceryl cocoate prepared using the composite catalyst and azeotropic dehydration purification technology of this invention on emulsion stability and oil solubilization ability.

[0068] Control group E4: No pH adjustment group Solution: In step S3, the step of adjusting the pH with organic acid is omitted, and the original pH value of the system is maintained (approximately 8.5-9.0). The remaining components and processes are the same as in Example 2.

[0069] Objective: To isolate and verify the key role of pH-responsive stabilization technology, which involves adjusting the pH to 6.0-7.0 with organic acids to protonate amino groups, in the long-term stability of emulsions.

[0070] Control group E5: Traditional bulk emulsification group Procedure: Comparative samples were prepared using a conventional bulk emulsification process. A conventional amino silicone oil without polyether blocks (using γ-piperazinylpropylmethyldimethoxysilane, polymerization process as in Example 2) was pre-synthesized and used as the silicone oil. 12% fatty alcohol polyoxyethylene ether (AEO-9) was added as an emulsifier, and the mixture was sheared and dispersed at 10,000 rpm for 20 min in a high-speed shear mill. The dosage and process of the remaining components (polyether block copolymer, organic acid, preservative, deionized water) were the same as in Example 2.

[0071] Objective: To establish a benchmark for existing technologies and verify the advantages of the self-emulsifying system of this invention over traditional external emulsifier processes in terms of emulsifier dosage, particle size control, and mildness.

[0072] Control group E6 (Example 2 of the present invention): Complete synergistic structure group Scheme: The complete scheme of this invention is adopted, namely 30% amino-modified silicone oil (γ-piperazine structure), 10% PEG-7 glycerol cocoate (composite catalytic azeotropic dehydration purification), 10% polyether block copolymer, 0.2% organic acid, 0.5% preservative, and the balance deionized water, prepared according to the process of Example 2.

[0073] Following the identical physicochemical performance testing, stability testing, and application performance testing methods described above, samples E1, E2, E3, E4, E5, and E6 from the control group were tested. Key performance data are compared in Table 4. Figure 2-3 As shown.

[0074] Table 4 Comparative Experimental Performance Data According to Table 4 and Figure 2-3 It can be concluded that: 1. The crucial role of γ-piperazinylpropylmethyldimethoxysilane in introducing polyamine segments (comparison of E6 and E1) Results: The yellowing index of the conventional amino-modified group (E1) was as high as 8.5%, which was much higher than that of the E6 group (2.1%). At the same time, its average particle size increased to 156.3 nm (exceeding the target of 150 nm), the Zeta potential dropped to +28.4 mV, and slight stratification was observed in centrifugal stability.

[0075] Mechanism: Group E1 employs a conventional aminoethylaminopropyl structure. Its primary amine group is prone to oxidative degradation under heating or oxidative conditions, generating chromophores and leading to yellowing. Furthermore, its molecular chain regularity and steric hindrance are inferior to the γ-piperazinyl structure, resulting in insufficient molecular density during self-emulsification, inadequate interfacial film strength, increased emulsion particle size, and decreased potential. This invention (E6) introduces secondary and tertiary amine structures through γ-piperazinylpropylmethyldimethoxysilane, maintaining good adsorption properties while significantly inhibiting amine group oxidative yellowing. Simultaneously, its unique spatial configuration helps form a denser interfacial adsorption layer, enhancing emulsion stability.

[0076] 2. The synergistic necessity of specific mass ratios (2-9:1) of amino-modified silicone oil and PEG-7 glyceryl cocoate (comparison of E6 and E2) Results: In the ratio deviation group (E2), after the mass ratio was adjusted to 1:1, the average particle size increased sharply to 198.7 nm, the PDI reached 0.312, the centrifugal stability showed obvious oil floating, and the grease carrying capacity decreased to 3%.

[0077] Mechanism: In group E2, the proportion of PEG-7 glycerol cocoate was too high. Although its molecules have emulsifying ability, excessive presence can disrupt the orderly arrangement of amino-modified silicone oil at the oil-water interface, leading to a loose interfacial film structure and coarsened and unevenly distributed emulsion particles. This invention (E6) controls the mass ratio within the range of 2-9:1, achieving a synergistic arrangement between amino-modified silicone oil and PEG-7 glycerol cocoate—amino silicone oil provides the framework and primary emulsifying ability, while PEG-7 glycerol cocoate fills the gaps and solubilizes at the interface, forming a dense composite interfacial film, thereby achieving nanoscale particle size and ultra-high oil carrying capacity (10%).

[0078] 3. Contribution of composite catalyst and azeotropic dehydration technology to the preparation of high-purity PEG-7 glycerol cocoate (comparison of E6 and E3) Results: Although the conventional esterification group (E3) used the same raw material ratio, the particle size was slightly larger (145.2 nm), the oil carrying capacity (6%) was significantly lower than that of the E6 group (10%), and the light transmittance (88.5%) was also lower than that of the E6 group (92.5%).

[0079] Mechanism: Group E3 uses p-toluenesulfonic acid as a single catalyst, resulting in poor selectivity in the esterification reaction and easy generation of byproducts. Furthermore, it lacks azeotropic dehydration purification, leading to residual free fatty acids, monoesters, and catalyst residues in the product that interfere with the orderly assembly of the emulsion interface, reducing the density and solubilization capacity of the interfacial film. This invention (E6) employs a composite catalyst of p-toluenesulfonic acid and phosphorous acid. The synergistic catalytic effect of phosphorous acid improves reaction selectivity, and combined with azeotropic dehydration to promptly remove generated water, it propels the reaction equilibrium towards the high-purity target ester. Impurities are then removed by adsorption with activated clay, yielding high-purity, narrow-distribution PEG-7 glycerol cocoate, providing a high-quality auxiliary emulsifying and solubilizing component for the subsequent formation of a stable nanoemulsion.

[0080] 4. The key role of pH-responsive stabilization technology (comparison between E6 and E4) Results: The group without pH adjustment (E4) maintained the original pH of the system (approximately 8.5-9.0), and its average particle size increased to 168.5 nm, the Zeta potential decreased to +22.3 mV, centrifugal stability showed stratification, and both heat and cold resistance showed flocculation.

[0081] Mechanism: Under alkaline conditions, the amine groups in the amino-modified silicone oil of group E4 mainly exist in the form of free amines, resulting in weak intermolecular hydrogen bonding and insufficient interfacial film strength. This invention (E6) adjusts the pH to 6.0-7.0 using an organic acid, causing the protonated amines to form ammonium salts. This enhances the electrostatic repulsion between molecules and the mechanical strength of the interfacial film. Simultaneously, the protonated amine groups form a stronger hydrogen bond network with the aqueous phase, significantly improving the long-term stability of the emulsion.

[0082] 5. The essential difference between the self-emulsifying system of this invention and the traditional external emulsifier process (comparison of E6 and E5) Results: Despite the addition of 12% AEO-9 emulsifier, the conventional bulk emulsification group (E5) still had an average particle size of 235.6 nm, a PDI of 0.356, obvious stratification in centrifugal stability, an oil carrying capacity of only 3%, and a light transmittance of only 68.2%.

[0083] Mechanism: Group E5 relies on external emulsifiers to be mechanically adsorbed at the oil-water interface. Its emulsification efficiency is limited by shear strength and the affinity between emulsifier molecules and the oil phase, making it difficult to form a uniform and dense interfacial film. Furthermore, the external emulsifier is prone to desorption and migration, resulting in poor long-term stability. This invention (E6) achieves the intrinsic self-emulsification capability of amino silicone oil by directly embedding polyether segments into the polysiloxane backbone. The emulsifying groups are chemically bonded to the oil phase, never desorbing, and the resulting interfacial film has higher strength and density. At the same time, it completely eliminates the need for external emulsifiers, fundamentally solving the problems of irritation and environmental burden caused by surfactant residues.

[0084] in conclusion: The comparative experiments of the above systems fully demonstrate that the molecular design of introducing polyamine segments into γ-piperazinylpropylmethyldimethoxysilane, the synergistic system of a specific mass ratio (2-9:1) of amino-modified silicone oil and PEG-7 glycerol cocoate, the preparation of high-purity PEG-7 glycerol cocoate using composite catalysts and azeotropic dehydration technology, and the pH-responsive stabilization technology proposed in this invention constitute an organically synergistic and indispensable technical system. This design successfully solves the chain reaction problems of severe yellowing, poor stability, high emulsifier dosage, and insufficient oil carrying capacity in traditional amino silicone oil emulsions. The absence or deviation of any single feature will lead to a significant and observable regression in key indicators such as particle size control, stability, anti-yellowing performance, or oil solubilization capacity of the emulsion. The technical effect of this invention is by no means a simple summation of the properties of each component, but rather an unexpected technical breakthrough achieved through the synergistic effect of specific structures and process parameters.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a self-emulsifying amino silicone oil emulsion, characterized in that, Includes the following steps: Step S1: First, weigh out the following ingredients according to their mass percentages: 20-40% amino-modified silicone oil, 5-20% PEG-7 glyceryl cocoate, 5-15% polyether block copolymer, 0.1-0.5% organic acid, 0.3-0.8% preservative, and the remainder is deionized water. The amino-modified silicone oil is a ternary copolymer block structure polysiloxane, which is obtained by polymerization reaction from the following raw materials in the indicated mass proportions: 5-15% γ-piperazinylpropylmethyldimethoxysilane, 1-3% hexamethyldisiloxane, 0.5-1% basic catalyst, with the balance being octamethylcyclotetrasiloxane; The PEG-7 glyceryl cocoate is obtained by esterification of the following raw materials in the indicated mass percentages: Coconut oil acid 30-40%, composite catalyst 0.3-0.8%, balance glycerol polyoxyethylene ether-7; Step S2: Mix amino-modified silicone oil with PEG-7 glyceryl cocoate, add polyether block copolymer and deionized water, and stir to form a self-emulsifying pre-dispersion; Step S3: Add organic acid to the self-emulsifying pre-dispersion to adjust the pH to 6.0-7.0, and then transfer the system to a homogenizer to refine the emulsion particle size to below 150nm; Step S4: Transfer the homogenized emulsion to a mixing tank and stir at room temperature for 2-4 hours for stabilization; finally, add preservatives, mix evenly, filter and discharge to obtain self-emulsifying amino silicone oil emulsion.

2. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 1, characterized in that: In step S1, octamethylcyclotetrasiloxane, γ-piperazinylpropylmethyldimethoxysilane, hexamethyldisiloxane and alkaline catalyst are added to a reaction vessel, and the temperature is raised to 80-90°C under nitrogen protection, and the reaction is carried out for 1-2 hours to perform ring-opening polymerization. The temperature was then raised to 100-110℃ and the reaction continued for 6-8 hours to complete chain growth. Finally, the temperature was raised to 130-140℃ under vacuum conditions of ≤-0.095 MPa to remove low molecular weight substances for 1 hour. The product was then cooled and discharged to obtain amino-modified silicone oil.

3. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 1, characterized in that: In step S1, glycerol polyoxyethylene ether-7 and coconut oil acid are added to a reaction vessel, along with a composite catalyst and an azeotropic solvent. Heat to 165-175℃ and perform an azeotropic dehydration reaction for 4-6 hours until the theoretical water yield reaches over 95%. After the reaction was completed, the temperature was raised to 120-130℃ under a vacuum of ≤-0.095 MPa, and the azeotropic solvent was recovered by vacuum distillation. Cool to 80-90℃, add a neutralizing agent to adjust the pH to 6.0-7.0, add activated clay or activated carbon and stir to adsorb for 30 minutes, then filter to obtain PEG-7 glycerol cocoate.

4. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 3, characterized in that: The composite catalyst is composed of p-toluenesulfonic acid and phosphorous acid in a mass ratio of 2:

1.

5. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 1, characterized in that: In step S2, amino-modified silicone oil and PEG-7 glyceryl cocoate are mixed at a mass ratio of 2-9:

1.

6. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 1, characterized in that: In step S2, the mixture is stirred at 40-60°C for 30-60 minutes to form a self-emulsifying pre-dispersion.

7. The method for preparing the self-emulsifying amino silicone oil emulsion according to claim 1, characterized in that: In step S3, the system is homogenized in a homogenizer at 5000-8000 rpm for 10-20 min.

8. A self-emulsifying amino silicone oil emulsion prepared by the preparation method according to any one of claims 1-7, characterized in that, Including the following raw materials: Amino-modified silicone oil, PEG-7 glyceryl cocoate, polyether block copolymer, organic acid, preservative and deionized water.

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