A method for preparing a stable aminosilicone oil emulsion by regulating the electrical properties and potential of silica sol particles and the emulsion

Abstract

The present invention discloses a method and an emulsion for preparing a stable aminosilicone oil emulsion by regulating the electrical properties and potential of silica sol particles, and a method for preparing a stable aminosilicone oil emulsion by regulating the electrical properties of silica sol particles. The mass ratio of each material in the silicone oil emulsion is as follows: 20-30 parts by weight of aminosilicone oil, 2-5 parts by weight of emulsifier, 2-5 parts by weight of silica sol particles, 1-3 parts by weight of pH regulator, and 60-80 parts by weight of deionized water, and a specific preparation method is provided. The present invention solves the problems of poor stability and high emulsifier dosage of traditional silicone oil emulsions, and the prepared silicone oil emulsion has excellent dispersion stability; at the same time, it has the characteristics of low cost and simple process.

Description

Technical Field

[0001] The present invention relates to the field of textile auxiliaries, and in particular to a method for preparing an amino silicone oil emulsion by coupling modified silica sol particles to adjust the electrical properties and potential of the particles and then using the particles in the emulsification process of amino silicone oil. Background Art

[0002] Due to their high molecular chain flexibility and low interfacial energy, silicone oils are widely used in textile finishing processes, significantly enhancing their softness when applied to textile fiber surfaces. Currently, silicone oils are primarily formulated into emulsions in the textile industry, with amino-functional silicone oils being the primary choice. However, these silicone oil emulsions suffer from low dispersion stability and are prone to instability during storage, such as oil bleaching.

[0003] Currently, the primary method for improving the dispersion stability of silicone oil emulsions is to increase the dosage of surfactants, most of which are nonionic. During silicone oil emulsification, the added nonionic surfactant adsorbs on the surface of the silicone oil droplets, reducing the interfacial tension between the silicone oil droplets and the aqueous phase. Furthermore, the hydrophilic segment of the emulsifier creates a "steric hindrance" between the silicone oil droplets, inhibiting irreversible collisions and coalescence between the droplets, thereby improving the dispersion stability of the silicone oil emulsion. However, since emulsifiers are "dynamically adsorbed" on the oil droplet surface, the amount of surfactant added is very high. High dosages of surfactant not only increase emulsion production costs, but also form a thick hydrophilic layer on the oil droplet surface that hinders silicone adsorption to the fabric, reducing the efficacy of the additive. High concentrations of additive residues also increase the chemical oxygen demand (COD) in the residual liquid and increase the burden on wastewater treatment. Therefore, developing new methods for preparing highly stable silicone oil emulsions has become an urgent industry challenge.

[0004] Ramsden (Proceedings of the Royal Society of London, 1904, 72(477-486):156-164) reported a method for stabilizing emulsions using solid particles as stabilizers. The solid particles adsorbed on the surface of the droplets provide a mechanical barrier, similar to armor, that prevents the droplets from coalescing due to collisions, thereby significantly improving the dispersion stability of the emulsion. There are also reports on using particles such as silica sol as solid particles to improve the dispersion stability of silicone oil emulsions. For example, Binks et al. (Soft Matter, 2016, 12:876-887) used silica as a solid particle substitute for an emulsifier to prepare an amino-free polydimethylsilicone (PDMS) emulsion. During the emulsification of the silicone oil, silica was gradually added to the oily PDMS in the form of an aqueous dispersion. By adjusting the amphiphilicity of the silica particles, silica was adsorbed on the surface of the PDMS droplets. A PDMS emulsion stabilized with amphiphilic modified silica was prepared. The effect of silica particle size on emulsion stability was also studied. This technique provides some guidance for preparing stable silicone oil emulsions, but it cannot be directly used to prepare silicone oil emulsions for textile finishing softeners. The reason is that the silicone oil used is PDMS, which does not contain amino groups in its molecules and is therefore unsuitable for textile finishing. Furthermore, the study did not explore the possible effects of the electrical properties of the silica sol particles on emulsion preparation and dispersion stability.

[0005] Patents CN117888357A and KR101420645B1, respectively, report methods for preparing functional textile auxiliaries by adding silica sol or acrylic resin particles to an amino silicone oil emulsion. However, in both patents, the silica sol and acrylic resin particles are added after the silicone oil has formed an emulsion; the particles do not participate in the emulsification process of the silicone oil from oil to emulsion.

[0006] Patents CN113698626A and CN116084172A disclose aminosilicone oil emulsions stabilized by soft and hard nanoparticles, respectively, and their preparation methods: the former is compounded by an emulsifier with soft polymer particles (such as PEHA, PBA or PPA), and the latter is compounded by an emulsifier with hard polymer particles (such as PMMA, PIBoMA), both of which improve the dispersion stability of aminosilicone oil emulsions. The paper (Journal of Textile Research, 2024, 45(01): 136-145) reports a method for stabilizing aminosilicone oil emulsions by compounding poly (isooctyl acrylate) (PEHA) particles with an emulsifier. Experiments show that increasing the size of PEHA particles and improving the amphiphilicity of the PEHA particle surface both help to improve the dispersion stability of the silicone oil emulsion. However, the above cases only involve the effects of particle size and amphiphilicity on the stability of aminosilicone oil emulsions, and do not involve the effects of the electrical properties and potential of the particles used on the stability of polar silicone oil emulsions.

[0007] Patent CN117535975A proposes a method for stabilizing amino silicone oil emulsions using anionic polymer nanoparticles. This method involves adsorbing cationic silicone oil onto an anionic acrylate emulsion (e.g., PBA, PPA, PEHA). However, this method does not consider the effect of particle potential on emulsion stability. When the particle potential is low, flocculation is likely to occur when encountering antiparticles or due to pH changes. Binks pointed out in his research (Langmuir, 2000, 16(23), 8622-8631) that the flocculents cannot be evenly distributed on the droplet surface, thus losing their "mechanical barrier" effect, causing droplet aggregation and exacerbating the oil-water stratification phenomenon. Summary of the Invention

[0008] To address the challenges of the prior art, the present invention provides an aminosilicone oil emulsion and a method for preparing the aminosilicone oil emulsion by coupling modified silica sol particles to adjust the electrical properties and potential of the particles, which are then used in the emulsification process of aminosilicone oil. The method for regulating the electrical properties and potential of the silica sol particles to stabilize the aminosilicone oil emulsion involves adsorbing cationic oil droplets onto the surface of polar particles to form a "mechanical barrier" that inhibits the coalescence of the oil droplets. This addresses the poor stability and high emulsifier requirements of traditional silicone oil emulsions, resulting in excellent emulsion stability. Furthermore, the method is low-cost and simple to manufacture.

[0009] In an emulsion stabilized by solid particles, stable adsorption of the solid particles on the droplet surface is crucial for achieving emulsion stability. Factors driving adsorption include the amphiphilicity of the particles and their size. For aminosilicone oils, the ionization of amino groups in water and their reaction with acids impart positive charge to the aminosilicone oil, generating electrostatic forces between the amino group and the added solid particles, affecting their adsorption behavior on the surface of the aminosilicone oil droplets. The strength of this electrostatic force is closely related to the particle's electrical properties, namely its zeta potential. Furthermore, the particle's electrical properties can affect its dispersion in solution, further influencing its adsorption at the interface. However, this issue is not addressed in the aforementioned prior art.

[0010] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0011] An aminosilicone oil emulsion is stabilized by regulating the electrical properties and potential of silica sol particles. The mass ratio of the aminosilicone oil emulsion is as follows: aminosilicone oil: 20 to 30 parts by weight; emulsifier: 2 to 5 parts by weight; silica sol: 2 to 5 parts by weight; pH regulator: 1 to 3 parts by weight; and deionized water: 60 to 80 parts by weight.

[0012] Preferably, the emulsifier is isomeric tridecanol ethoxylate.

[0013] Preferably, the zeta potential of the silica sol is +10mv to +30mv or -50mv to -70mv, the particle size is 30 to 50nm, the pH is 6 to 7, and the concentration is 20% to 40%.

[0014] Preferably, the amino silicone oil has an ammonia value of 0.2 to 0.5 and a viscosity of 2000 to 4000 mPa.s.

[0015] Preferably, the mass fraction ratio of silica sol to amino silicone oil is 1:10 to 3:10.

[0016] Preferably, the mass fraction ratio of emulsifier to amino silicone oil is 1:10 to 3:10.

[0017] Preferably, the concentration of the silicone oil emulsion is between 20% and 40%.

[0018] Preferably, the pH adjuster is acetic acid.

[0019] Preferably, the preparation method of the silicone oil emulsion comprises:

[0020] Add the amino silicone oil and emulsifier to a reaction vessel and stir at 800-1500 rpm for 10-30 minutes at room temperature. Then, slowly add the mixture of silica sol and deionized water while stirring and continue stirring for 30-90 minutes to obtain a milky white and evenly dispersed silicone oil emulsion. The stirring of the raw materials can be adjusted in order as needed.

[0021] It can be seen from the above description that the present invention has the following advantages:

[0022] 1. The present invention solves the problems of poor stability and high emulsifier usage of traditional silicone oil emulsions, and has excellent emulsion stability and application performance; at the same time, it also has the characteristics of low cost and simple process.

[0023] 2. In the silica sol-stabilized silicone oil emulsion of the present invention, the silica sol forms a physical barrier on the surface of the silicone oil droplets by adsorbing on the "silicone oil / water" interface. Through the interfacial repulsion effect, it blocks the interfacial oil-water interaction and the irreversible contact between the droplets, thereby inhibiting the coalescence of the oil droplets. Moreover, this interfacial adsorption behavior of the particles is irreversible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The appearance of the emulsions of Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6 after standing for 60 days;

[0025] Figure 2 The appearance of the emulsions of Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6 and Comparative Example 7 after standing for 60 days; DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to specific embodiments, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all within the scope of protection of the present invention.

[0027] A method for stabilizing an aminosilicone oil emulsion by regulating the electrical properties and potential of silica sol particles comprises the following steps:

[0028] The preparation method of the silicone oil emulsion in Examples 1 to 6 comprises the following steps:

[0029] (1) Amino silicone oil (ammonia value of 0.3, viscosity of 3000 mPa.s) and isomeric tridecanol ethoxylate were placed in a reaction vessel for high-speed shear emulsification, with a stirring time of 20 min, a rotation speed of 900 r / min, and a stirring temperature of 25°C;

[0030] (2) In another container, 2.5 parts by weight of silica sol and 70 parts by weight of deionized water were mixed evenly, wherein the silica sols with different surface electrical properties were as shown in Table 1;

[0031] (3) Slowly adding the mixed solution obtained in step (2) to the system obtained in step (1) while adding dropwise for 60-90 minutes while stirring;

[0032] (4) Adding acetic acid to the system obtained in step (3) to adjust the pH to 6.0-7.0 to obtain the amino silicone oil emulsion stabilized by the silica sol.

[0033] Table 1: Formulas of Examples 1 to 6

[0034]

[0035] Note: 1. The remaining substance is deionized water, and the total weight is 100 parts.

[0036] 2. The properties and preparation method of silica sol are shown in Table 3.

[0037] The preparation method of Comparative Example 1 is the same as that of Example 1, except that no silica sol particles are added in step (2) of Comparative Example 1, and the amount of the emulsifier isomeric tridecyl alcohol ethoxylate is increased to 5 parts by weight.

[0038] The preparation methods in Comparative Examples 2 to 7 are the same as those in Example 1.

[0039] Table 2 Comparative Examples 1 to 7 Formulas

[0040]

[0041] Note: 1. The remaining substance is deionized water, and the total weight is 100 parts.

[0042] 2. The properties and preparation method of silica sol are shown in Table 3.

[0043] Table 3 Potential control formula of silica sol particles and product performance in examples and comparative examples

[0044]

[0045] Note: 1. The silica sol raw material used for potential regulation is non-ionic silica sol dispersion with a concentration of 30% and an average particle size of 40-43 nm.

[0046] 2. Method for Controlling Silica Sol Potential: According to Table 3, weigh a certain amount of silica sol raw material and add it to anhydrous ethanol. Mechanically stir and mix thoroughly to obtain a 10% silica sol ethanol dispersion. Add the silica sol ethanol dispersion to a 250ml jacketed reactor. Start a water bath circulation device and maintain the reaction temperature at 25°C. Referring to the scheme in Table 3, add a certain amount of silane coupling agent dropwise to the jacketed reactor. After reacting for 24 hours under magnetic stirring, silica sols with different surface electrical properties are obtained.

[0047] Table 4 Static stability results of emulsions

[0048]

[0049] Description of the characterization methods involved in the examples and comparative examples:

[0050] Static stability test: The prepared emulsion is placed in a glass bottle and placed at room temperature. The emulsion is observed within 30 days to see if there are any unstable phenomena such as stratification, precipitation, turbidity, crystallization, etc.

[0051] Centrifugal stability: Place the emulsion in a 50 mL centrifuge tube and centrifuge at 3000 r / min for 45 min. Then take out the emulsion and observe and record its appearance.

[0052] Particle size and Zeta potential test: 0.5 mL of the sample to be tested was diluted 1000 times with deionized water, and then placed in an ultrasonic cleaner for ultrasonic treatment for 30 min to disperse the latex particles in water. The zeta potential and particle size of the sample to be tested were tested at 25°C using a Nano S90 dynamic light scattering nanoparticle size analyzer (Malvern Instruments Ltd., UK).

[0053] Amphiphilicity testing: 10 μL of Pickering particle emulsion was dropped onto a glass slide pre-mounted on the rotating stage of a spin coater. The spin coater was turned on and set to 3000 rpm for 30 seconds. The spin-coated glass slide was then dried in an oven at 60°C. The static water contact angle of the coating was measured using a DSA 20 video contact angle tensiometer (K ​​RUSS Scientific Instruments GmbH, Germany). During this time, a 2 μL drop of deionized water was placed on the sample surface and allowed to stand for 30 seconds. The contact angle was calculated using a five-point fitting method. Five different locations on each sample were tested, and the average value was calculated.

[0054] Figure 1 The appearance of the emulsions of Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6 after standing for 60 days; Figure 2 This is the appearance of the emulsions of Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6 and Comparative Example 7 after standing for 60 days.

[0055] 1. Comparison of Example 1, Example 2, Example 3, Example 4 and Comparative Example 1: It shows that compared with the emulsifier system alone, after potential regulation, the silica sol particles improve the stability of the amino silicone oil emulsion.

[0056] 2. Comparison of Example 1, Example 2, Example 3, Example 4 and Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5 shows that the particles can form stable adsorption on the interface only when the Zeta potential is 0 to +30 mv or -70 mv to -30 mv. The reasons are as follows: when the Zeta potential of the silica sol is -70mv~-30mv, the strong negative charge of the particles generates an electrostatic attraction with the cationic interface, driving the particles to adsorb on the interface and thus stabilize the emulsion; when the Zeta potential of the silica sol is at -30mv~0mv, due to the weak surface charge of the particles, the weakly negatively charged particles flocculate under the neutralization of the positively charged groups on the surface of the amino silicone oil, weakening the adsorption density of the particles on the interface and thus failing to stabilize the emulsion; when the Zeta potential of the silica sol is 0~+30mv, there is a weak electrostatic repulsion between the weakly positively charged particles and the interface, but this repulsion is not enough to completely repel the particles from the interface. Therefore, the particles can form an appropriate adsorption density on the interface, forming a mechanical barrier layer, thereby stabilizing the emulsion; and when the Zeta potential increases to +30~+70mv, the positive charge of the particles is too strong, generating significant electrostatic repulsion with the positive charge on the amino silicone oil interface, further weakening the adsorption of the particles on the interface, making it difficult for the emulsion to remain stable.

[0057] 3. Comparison of Example 5 and Comparative Example 6 shows that when the amphiphilicity of the silica sol is changed but the potential is not within the range described in 2 above, the silica sol cannot stabilize the amino silicone oil emulsion.

[0058] 4. Comparison of Example 6 and Comparative Example 7 shows that when the particle size of the silica sol is changed but the potential is not within the range described in 2 above, the silica sol cannot stabilize the amino silicone oil emulsion.

[0059] It is understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced with equivalents to achieve the same technical effects; as long as the use requirements are met, they are all within the scope of protection of the present invention.

Claims

1. An amino silicone oil emulsion, characterized in that Made from the following raw materials in parts by weight: 20-30 parts by weight of amino silicone oil; 2-5 parts by weight of emulsifier; 2-5 parts by weight of silica sol; 1-3 parts by weight of pH regulator; 60-80 parts by weight of deionized water; The emulsifier is tridecanol ethoxylate; The zeta potential of the particles in the silica sol is 0mv~+30mv or -30mv~-70mv, and the particle size is 30~50nm; The pH value of the amino silicone oil emulsion is 6.0-7.

0.

2. The amino silicone oil emulsion according to claim 1, wherein The amino silicone oil has an ammonia value of 0.2-0.5 and a viscosity of 2000-4000 mPa.s.

3. The amino silicone oil emulsion according to claim 1, wherein The pH regulator is acetic acid.

4. The method for preparing the amino silicone oil emulsion according to any one of claims 1 to 3, wherein The following steps are involved: Add amino silicone oil and emulsifier to a reaction container and stir, then add a mixture of silica sol and deionized water while stirring, add pH regulator, and continue stirring to obtain a milky white and uniformly dispersed amino silicone oil emulsion.

5. The method according to claim 4, wherein Stir at 800-1500 rpm for 10-30 min.

6. The method according to claim 4, wherein A pH adjuster was added to adjust the pH to 6.0-7.

0.

7. The method according to claim 4, wherein Continue stirring for 30-90 minutes.

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