Bentonite gel, preparation method therefor, and use thereof

Abstract

Disclosed is a bentonite gel, comprising the following components in parts by weight: 65-85 parts of grease, 12-22 parts of bentonite, and 5-12 parts of propylene glycol carbonate. The preparation method therefor comprises: stirring grease and bentonite at room temperature at a speed of 400-600 r / min for 15-30 min; then adding propylene glycol carbonate; stirring the mixture at a speed of 1200-1600 r / min for 60-180 s until it becomes viscous; and grinding the stirred product to obtain a bentonite gel. The bentonite gel can be used in cosmetics.

Description

A bentonite gel, its preparation method and application Technical Field

[0001] This application relates to the field of cosmetic ingredients, and more specifically, to a bentonite gel, its preparation method, and its application. Background Technology

[0002] As people's living standards improve and their health awareness increases, consumers are paying more and more attention to the quality and safety of cosmetics. They not only expect cosmetics to have good beautifying effects, such as moisturizing, whitening, and concealing, but also require products to be gentle on the skin, non-irritating, and free of harmful substances. The non-toxic nature of bentonite makes it one of the ideal choices to meet this consumer demand.

[0003] Bentonite is a clay mineral with montmorillonite as its main component. Its unique crystal structure endows it with a variety of excellent properties. Montmorillonite is a 2:1 type layered silicate mineral composed of two layers of silicon-oxygen tetrahedra sandwiching a layer of aluminum-oxygen octahedra. This structure gives it a large specific surface area and ion exchange capacity, thus exhibiting good adsorption properties. It can be compounded with a variety of cosmetic ingredients, meeting the diverse needs of cosmetic functions and formulations while reducing the risk of adverse reactions to the skin, providing consumers with safer and more reliable cosmetic products.

[0004] However, bentonite gels still suffer from insufficient stability in cosmetic applications. Bentonite gels are three-dimensional network structures formed by bentonite particles dispersed in a solvent. In this system, the surface of the bentonite particles carries an electrical charge. Due to factors such as electrostatic interactions, the particles can aggregate. For example, when the electrolyte concentration in the system changes, it compresses the electric double layer on the surface of the bentonite particles, reducing the electrostatic repulsion between particles and making them more likely to approach and aggregate. This aggregation disrupts the original network structure of the gel, leading to decreased gel stability. Because bentonite can adsorb oils, if the gel system lacks stability, external environmental factors, such as changes in pressure and temperature, can cause oils to be squeezed out or diffused from the gel structure. Summary of the Invention

[0005] To address the current issue of insufficient stability in the application of bentonite gels in cosmetics, this application provides a bentonite gel, its preparation method, and its application.

[0006] Firstly, the bentonite gel provided in this application adopts the following technical solution:

[0007] A bentonite gel, the components of which, by weight, include 65-85 parts of oil, 12-22 parts of bentonite, and 5-12 parts of propylene glycol carbonate.

[0008] By employing the above-described technical solution, the grease plays a crucial role in lubrication and moisturizing within the gel system, while also integrating with other components to form a stable structure. Bentonite, as the primary gelling agent, ensures a stable three-dimensional network structure when used in appropriate proportions. Propylene glycol carbonate helps regulate gel properties and enhances the binding force between components. The specific proportions in this application effectively avoid these problems, improve gel stability, prevent particle aggregation, and prevent oil exudation due to decreased stability.

[0009] Optionally, the grease includes one of cyclopentamethoxysiloxane, caprylic / capric triglyceride, hydrogenated polyisobutylene, isododecane, and polydimethylsiloxane.

[0010] By employing the above technical solutions, these oils can interact effectively with bentonite particles, further enhancing the stability of the gel. The interaction between the oils and bentonite can also regulate the viscosity and flowability of the gel, making it more suitable for cosmetic applications.

[0011] Optionally, the bentonite is an organic-inorganic composite modified bentonite, which is modified by both titanate coupling agent and γ-aminopropyltriethoxysilane coupling agent.

[0012] Optionally, the preparation method of the organic-inorganic composite modified bentonite is as follows:

[0013] The titanate coupling agent was mixed with anhydrous ethanol at a mass ratio of 1:10 and stirred at room temperature to form a modified solution.

[0014] The bentonite was dried, ground and passed through a 200-mesh sieve. The bentonite and the modified solution were mixed at a mass ratio of 1:(2.5-3.5) and stirred at 60-70℃ for 3-4 hours.

[0015] After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed with anhydrous ethanol and dried to obtain inorganic modified bentonite.

[0016] γ-aminopropyltriethoxysilane coupling agent was mixed with water at a mass ratio of 1:5, and acetic acid was added dropwise to adjust the pH of the solution to 4-5. The mixture was stirred at room temperature to form an organic modified solution.

[0017] Inorganic modified bentonite and organic modified solution were mixed at a mass ratio of 1:(1.5-2.5) and stirred at 40-50℃ for 4-5 hours. After the reaction was completed, the solid product was separated by filtration. The solid product was washed and dried to obtain organic-inorganic composite modified bentonite.

[0018] By employing the above technical solution, an inorganic protective layer is first formed on the surface of bentonite particles through dual modification with titanate coupling agent and γ-aminopropyltriethoxysilane coupling agent. The titanate coupling agent reacts with the hydroxyl groups on the surface of the bentonite particles, constructing a robust inorganic coating layer on the particle surface, enhancing the hardness and physical stability of the particles. This inorganic layer can effectively resist the influence of external factors such as temperature changes and pressure on the bentonite particles, reducing particle breakage and structural deformation, thus laying the foundation for gel stability. Next, organic modification is performed. The siloxane groups of the γ-aminopropyltriethoxysilane coupling agent react with the hydroxyl groups on the surface of the inorganic modified layer. The outward-extending organic groups give the bentonite better hydrophobicity and compatibility with organic components. In the bentonite gel system, this good compatibility allows the modified bentonite particles to be more uniformly dispersed in organic components such as oils, reducing particle aggregation and further enhancing gel stability.

[0019] Furthermore, the γ-aminopropyltriethoxysilane coupling agent endows bentonite with hydrophobic organic groups, enabling better interaction with oil molecules and increasing the binding force between them. Due to its unique structure and surface properties, the modified bentonite can more effectively adsorb oils. The combined effect of the inorganic and organic modification layers provides oil molecules with more adsorption sites and stronger adsorption forces. This robust adsorption makes the oils more stable in the gel system, less susceptible to migration or separation due to external factors.

[0020] Secondly, this application provides a method for preparing bentonite gel, which adopts the following technical solution:

[0021] A method for preparing bentonite gel includes the following steps:

[0022] The oil and bentonite were stirred at 400-600 rpm for 15-30 min at room temperature. Then, propylene glycol carbonate was added and stirred at 1200-1600 rpm for 60-180 s until it became viscous. The stirred product was then ground to obtain bentonite gel.

[0023] By employing the above technical solution, stirring the oil and bentonite at 400-600 r / min for 15-30 min at room temperature allows for initial uniform mixing of the oil and bentonite, ensuring the oil fully coats the bentonite particles and reducing local agglomeration. After adding propylene glycol carbonate, the stirring speed is increased to 1200-1600 r / min and stirred for 60-180 s until a viscous consistency is reached. The higher stirring speed allows the propylene glycol carbonate to disperse rapidly in the oil and bentonite mixture, promoting interaction among the three components. As an additive, propylene glycol carbonate can regulate gel properties; under high-speed stirring, it better binds with the oil and bentonite, further optimizing the system's homogeneity. Through the control of the preparation conditions described in this application, the formation and stability of the three-dimensional structural framework in the bentonite gel can be maximized. Grinding the stirred product further disperses the bentonite particles more uniformly in the gel system, reducing particle agglomeration and size inhomogeneity. The method described in this application is time-efficient, low-cost, and relatively simple to operate, making it highly suitable for large-scale production. It has broad application prospects in the cosmetics, makeup, and skincare industries.

[0024] Optionally, the grinding is performed using a three-roll mill, wherein the front roller spacing is 7-10 μm and the rear roller spacing is 5-8 μm.

[0025] By employing the above technical solution, during the three-roll mill grinding process, by setting the front roller spacing to 7-10 μm and the rear roller spacing to 5-8 μm, the bentonite gel experiences strong extrusion and shear forces as it passes through these relatively small gaps. This effectively breaks down agglomerated particles in the gel, further refining the bentonite particles. After three-roll mill grinding, the refined and uniform distribution of bentonite particles facilitates the formation of a more stable three-dimensional network structure. The finer particles can better interweave, forming a denser network, thereby enhancing the gel's cohesion and stability.

[0026] Optionally, the grinding process may be repeated 1-2 times.

[0027] Thirdly, this application provides an application of bentonite gel, employing the following technical solution:

[0028] An application of a bentonite gel, wherein the bentonite gel is used in creams, lotions, and masks.

[0029] By adopting the above technical solution, the bentonite gel of this application can enhance the stability of creams, lotions and masks, prevent oil-water separation, extend shelf life and improve moisturizing and nourishing effects.

[0030] In summary, this application has the following beneficial effects:

[0031] 1. Since this application uses grease to play a lubricating and moisturizing role and integrates with other components to form a stable structure, bentonite as the main gel forming agent ensures a stable three-dimensional network structure in an appropriate proportion, and propylene glycol carbonate adjusts the gel properties and enhances the binding force of the components. This specific proportion can effectively avoid particle aggregation and oil leakage problems caused by decreased stability, thereby improving the overall stability of the gel.

[0032] 2. In this application, dual modification is preferably performed using a titanate coupling agent and a γ-aminopropyltriethoxysilane coupling agent. First, the titanate coupling agent reacts with the hydroxyl groups on the surface of the bentonite particles to form an inorganic protective layer, which enhances the hardness and physical stability of the particles, resists the influence of external factors, and lays the foundation for gel stability. Then, the siloxane groups of the γ-aminopropyltriethoxysilane coupling agent react with the hydroxyl groups of the inorganic modification layer, making the bentonite hydrophobic and compatible with organic components. This allows the modified bentonite particles to be more uniformly dispersed in organic components such as oils, reducing aggregation and further enhancing gel stability. The hydrophobic organic groups imparted by the agent can also enhance the interaction and binding force with oil molecules. Furthermore, the inorganic and organic modification layers together provide more adsorption sites and stronger adsorption forces for oil molecules, making the oil more stable in the gel system and less susceptible to migration or separation due to external factors.

[0033] 3. The method of this application ensures the formation and stability of the three-dimensional structure framework of bentonite gel by controlling the preparation conditions. After stirring, grinding can make the bentonite particles more uniformly dispersed, reducing agglomeration and inhomogeneity. This method is time-saving, low-cost, and simple to operate, and is suitable for large-scale production. It has broad application prospects in the cosmetics, makeup and skin care industries. Detailed Implementation

[0034] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0035] Preparation Example 1

[0036] Preparation of an organic-inorganic composite modified bentonite:

[0037] Mix 1 kg of titanate coupling agent with 10 kg of anhydrous ethanol in a clean container and stir at room temperature for 30 minutes to fully dissolve the titanate coupling agent and form a uniform inorganic modified solution.

[0038] The bentonite was dried at 110℃ for 2 hours to remove the moisture, and then ground through a 200-mesh sieve. 1 kg of bentonite was mixed with 3 kg of inorganic modification solution and stirred at 65℃ for 4 hours.

[0039] After the reaction was completed, the solid product was separated by centrifuging at 3000 r / min for 10 minutes. The solid product was washed three times with anhydrous ethanol to remove unreacted modifier. The washed solid product was dried at 85℃ for 8 hours to obtain inorganic modified bentonite.

[0040] Mix 1 kg of γ-aminopropyltriethoxysilane coupling agent with 5 kg of deionized water, and slowly add 3% (w / w) dilute acetic acid to adjust the pH of the solution to 4-5. Stir evenly at room temperature to form an organic modified solution.

[0041] 1 kg of inorganic modified bentonite was mixed with 2 kg of organic modified solution and stirred at 45 °C for 5 hours. After the reaction was completed, the solid product was separated by filtration through a filter screen. The solid product was washed with deionized water and dried at 60 °C to obtain organic-inorganic composite modified bentonite.

[0042] Preparation Example 2

[0043] Preparation of an inorganic composite modified bentonite:

[0044] Mix 1 kg of titanate coupling agent with 10 kg of anhydrous ethanol in a clean container and stir at room temperature for 30 minutes to fully dissolve the titanate coupling agent and form a uniform inorganic modified solution.

[0045] The bentonite was dried at 110℃ for 2 hours to remove the moisture, and then ground through a 200-mesh sieve. 1 kg of bentonite was mixed with 3 kg of inorganic modification solution and stirred at 65℃ for 4 hours.

[0046] After the reaction was completed, the solid product was separated by centrifuging at 3000 r / min for 10 minutes. The solid product was washed three times with anhydrous ethanol to remove unreacted modifier. The washed solid product was dried at 85℃ for 8 hours to obtain inorganic modified bentonite.

[0047] Example

[0048] In this application, cyclopentamethoxysiloxane, octanoic acid / caprylic acid triglyceride, hydrogenated polyisobutylene, isododecane, and polydimethylsiloxane were all purchased from Maclean's reagent and were of analytical grade. Bentonite was Maclean's reagent B802109. Propylene glycol carbonate was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd. and was of analytical grade. Titanate coupling agent was Hubei Longxin Chemical TMC-132. γ-aminopropyltriethoxysilane coupling agent was Merck's reagent and was of analytical grade.

[0049] Example 1

[0050] A method for preparing bentonite gel:

[0051] Add 650g of oil and 120g of bentonite to a mixing tank. The oil used is cyclopentamethoxysilane. Stir at 500r / min for 20min at room temperature. Then add 50g of propylene glycol carbonate and stir at 1400r / min for 120s until it becomes viscous. Grind the product using a three-roll mill with a front roller spacing of 7-10μm and a rear roller spacing of 5-8μm. Grind once to obtain bentonite gel.

[0052] Example 2

[0053] A method for preparing bentonite gel:

[0054] Add 750g of oil and 180g of bentonite to a mixing tank. The oil used is cyclopentamethoxysilane. Stir at 500r / min for 20min at room temperature. Then add 90g of propylene glycol carbonate and stir at 1400r / min for 120s until it becomes viscous. Grind the product using a three-roll mill with a front roller spacing of 7-10μm and a rear roller spacing of 5-8μm. Grind once to obtain bentonite gel.

[0055] Example 3

[0056] A method for preparing bentonite gel:

[0057] Add 850g of oil and 220g of bentonite to a mixing tank. The oil used is cyclopentamethoxysilane. Stir at 500r / min for 20min at room temperature. Then add 120g of propylene glycol carbonate and stir at 1400r / min for 120s until it becomes viscous. Grind the product using a three-roll mill with a front roller spacing of 7-10μm and a rear roller spacing of 5-8μm. Grind once to obtain bentonite gel.

[0058] Example 4

[0059] A method for preparing bentonite gel: The difference from Example 2 is that the oil used is caprylic / capric triglyceride.

[0060] Example 5

[0061] A method for preparing bentonite gel: The difference from Example 2 is that the oil used is hydrogenated polyisobutylene.

[0062] Example 6

[0063] A method for preparing bentonite gel: The difference from Example 2 is that the oil used is isododecane.

[0064] Example 7

[0065] A method for preparing bentonite gel: The difference from Example 2 is that the oil used is polydimethylsiloxane.

[0066] Example 8

[0067] A method for preparing bentonite gel: The difference from Example 2 is that 750g of oil and 180g of bentonite are added to a mixing tank, the oil being cyclopentamethoxysiloxane, and the mixture is stirred at 500r / min for 15min at room temperature.

[0068] Example 9

[0069] A method for preparing bentonite gel: The difference from Example 2 is that 750g of oil and 180g of bentonite are added to a mixing tank, the oil being cyclopentamethoxysiloxane, and the mixture is stirred at 500r / min for 30min at room temperature.

[0070] Example 10

[0071] A method for preparing bentonite gel: The difference from Example 2 is that the gel is stirred at 1200 r / min for 120 s until it becomes viscous.

[0072] Example 11

[0073] A method for preparing bentonite gel: The difference from Example 2 is that the gel is stirred at 1600 r / min for 120 s until it becomes viscous.

[0074] Example 12

[0075] A method for preparing bentonite gel: the difference from Example 2 is that it is ground twice by a three-roll mill.

[0076] Example 13

[0077] A method for preparing bentonite gel: The difference from Example 2 is that the distance between the front rollers in the three-roll mill is 4-7 μm and the distance between the rear rollers is 2-5 μm.

[0078] Example 14

[0079] A method for preparing bentonite gel: The difference from Example 2 is that the distance between the front rollers in the three-roll mill is 10-13 μm and the distance between the rear rollers is 8-11 μm.

[0080] Example 15

[0081] A method for preparing bentonite gel: The difference from Example 2 is that the bentonite used is an organic-inorganic composite modified bentonite, which was prepared by Example 1.

[0082] Comparative Example

[0083] Comparative Example 1

[0084] A method for preparing bentonite gel: The difference from Example 2 is that propylene glycol carbonate is replaced with an equal mass of propylene glycol.

[0085] Comparative Example 2

[0086] A method for preparing bentonite gel: the difference from Example 2 is that no grinding process is performed.

[0087] Comparative Example 3

[0088] A method for preparing bentonite gel: The difference from Example 15 is that the bentonite used is inorganic composite modified bentonite, which was prepared by Preparation Example 2.

[0089] Performance testing

[0090] Detection methods

[0091] Take 50g of each of the bentonite gels prepared above and test their viscosity using a viscometer at 50℃ and 50% humidity. Repeat the test after 7 days, 30 days and 90 days to evaluate the stability of the bentonite gel based on the change in viscosity.

[0092] Table 1 Test Data Statistics

[0093] As can be seen from Examples 2 and Comparative Examples 1-2, and in conjunction with Table 1, propylene glycol carbonate in this application helps to regulate the properties of the gel and enhance the binding force between the components. After three-roll milling, the refinement and uniform distribution of bentonite particles facilitates the formation of a more stable three-dimensional network structure. Smaller particles can better interweave with each other, forming a tighter network, thereby enhancing the cohesion and stability of the gel.

[0094] As can be seen from Examples 2 and 15 and Comparative Example 3, and in conjunction with Table 1, the inorganic layer, through dual modification with titanate coupling agent and γ-aminopropyltriethoxysilane coupling agent, effectively resists the influence of external factors such as temperature changes and pressure on bentonite particles. The organic modification gives bentonite better hydrophobicity and compatibility with organic components. In the bentonite gel system, this good compatibility allows the modified bentonite particles to be more uniformly dispersed in organic components such as oils, reducing particle aggregation and further enhancing gel stability.

[0095] As can be seen from Examples 1-3 and Table 1, the specific proportions in the present application can effectively avoid these problems, improve the stability of the gel, prevent particle aggregation, and prevent oil exudation due to decreased stability.

[0096] As can be seen from Examples 2 and 4-7, and in conjunction with Table 1, these oils can interact well with bentonite particles, further improving the stability of the gel. The interaction between the oils and bentonite can also regulate the viscosity and flowability of the gel, making it more suitable for cosmetic applications.

[0097] As can be seen from Examples 2 and 8-14, and Table 1, stirring the oil and bentonite at 400-600 r / min for 15-30 min at room temperature allows for initial uniform mixing of the oil and bentonite. The oil can fully coat the bentonite particles, reducing local agglomeration. After adding propylene glycol carbonate, the stirring speed is increased to 1200-1600 r / min and stirred for 60-180 s until a viscous consistency is reached. The higher stirring speed allows the propylene glycol carbonate to disperse rapidly in the mixture of oil and bentonite, promoting the interaction among the three components. By controlling the conditions during the preparation process in this application, the formation and stability of the three-dimensional structural framework in the bentonite gel can be maximized. During the three-roll mill grinding process, by setting the front roller spacing to 7-10 μm and the rear roller spacing to 5-8 μm, the bentonite gel is subjected to strong extrusion and shear forces when passing through these relatively small gaps, which can effectively break up the agglomerated particles in the gel and further refine the bentonite particles.

[0098] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A bentonite gel, characterized in that, Its components, by weight, include 65-85 parts of oil, 12-22 parts of bentonite, and 5-12 parts of propylene glycol carbonate.

2. The bentonite gel of claim 1, wherein: The oil comprises one of the following: cyclopentamethoxysiloxane, caprylic / capric triglyceride, hydrogenated polyisobutylene, isododecane, and polydimethylsiloxane.

3. The bentonite gel of claim 1, wherein: The bentonite is selected as organic-inorganic composite modified bentonite, which is modified by both titanate coupling agent and γ-aminopropyltriethoxysilane coupling agent.

4. The bentonite gel of claim 3, wherein: The preparation method of the organic-inorganic composite modified bentonite is as follows: The titanate coupling agent was mixed with anhydrous ethanol at a mass ratio of 1:10 and stirred at room temperature to form a modified solution. The bentonite was dried, ground and passed through a 200-mesh sieve. The bentonite and the modified solution were mixed at a mass ratio of 1:(2.5-3.5) and stirred at 60-70℃ for 3-4 hours. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed with anhydrous ethanol and dried to obtain inorganic modified bentonite. γ-aminopropyltriethoxysilane coupling agent was mixed with water at a mass ratio of 1:5, and acetic acid was added dropwise to adjust the pH of the solution to 4-5. The mixture was stirred at room temperature to form an organic modified solution. Inorganic modified bentonite and organic modified solution were mixed at a mass ratio of 1:(1.5-2.5) and stirred at 40-50℃ for 4-5 hours. After the reaction was completed, the solid product was separated by filtration. The solid product was washed and dried to obtain organic-inorganic composite modified bentonite.

5. A process for the preparation of the bentonite gel according to any one of claims 1-4, characterized in that: Includes the following steps: The oil and bentonite were stirred at 400-600 rpm for 15-30 min at room temperature. Then, propylene glycol carbonate was added and stirred at 1200-1600 rpm for 60-180 s until it became viscous. The stirred product was then ground to obtain bentonite gel.

6. The bentonite gel of claim 5, wherein: The grinding process uses a three-roll mill, where the distance between the front rollers is 7-10 μm and the distance between the rear rollers is 5-8 μm.

7. The bentonite gel of claim 5, wherein: The grinding process is repeated 1-2 times.

8. Use of the bentonite gel according to claim 1, characterized in that: The bentonite gel is used in creams, lotions, and face masks.

Images