Modified diatomite, modified diatomite-based pickering emulsion and preparation method thereof
By modifying diatomaceous earth, the skin irritation and environmental pollution problems of organic small molecule surfactants in emulsion cosmetics were solved, and a safe and stable Pickering emulsion was prepared, which improved the stability and adsorption of the emulsion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGCHUN INSTITUTE OF APPLIED CHEMISTRY CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2023-10-27
- Publication Date
- 2026-06-09
AI Technical Summary
Existing organic small-molecule surfactants in emulsion-type cosmetics are highly irritating to the skin and environmentally unfriendly, and diatomaceous earth has poor surface properties, making it difficult to use as an effective emulsifier for Pickering emulsions.
Modified diatomaceous earth was prepared by modifying its surface, ionizing silanol groups with an acidic catalyst and reacting them with the epoxy groups on glycidyl ether via nucleophilic substitution, thereby enhancing its hydrophobicity and increasing its water contact angle, and thus preparing a modified diatomaceous earth-based Pickering emulsion.
Modified diatomaceous earth-based Pickering emulsion is safe and non-toxic, non-irritating to the skin, and has excellent stability and adsorption properties, improving the overall skin feel and oil control effect of the emulsion.
Abstract
Description
Technical Field
[0001] This invention relates to the field of emulsion-type cosmetics technology, specifically to a modified diatomaceous earth, a modified diatomaceous earth-based Pickering emulsion, and a method for preparing the same. Background Technology
[0002] In emulsion-type cosmetics, organic small-molecule surfactants are an indispensable ingredient; without them, it is difficult, if not impossible, to formulate an oil-water emulsion. However, some surfactants are highly irritating to the skin, especially to sensitive skin. Furthermore, the production process of organic small-molecule surfactants raises concerns about VOC emissions and environmental pollution, making them environmentally unfriendly. Therefore, emulsion-type cosmetics place particular emphasis on the safety, non-toxicity, and efficacy of their raw materials, making the design and manufacture of alternatives to organic small-molecule surfactants a hot topic in the research and development of emulsion-type cosmetics.
[0003] Pickering emulsions are emulsions obtained using ultrafine solid particles as emulsifiers. Their biggest difference from traditional emulsions is the use of solid particles instead of traditional surfactants. Compared to emulsions stabilized by traditional surfactants, Pickering emulsions have the following advantages: (1) reduced dosage and lower cost; (2) non-toxic or less toxic than traditional surfactants, and environmentally friendly; (3) increased stability. Therefore, Pickering emulsions have significant application value in the pharmaceutical, cosmetic, food, and large-scale chemical production fields. Diatomaceous earth, as a natural material, is widely used due to its environmental friendliness, porous structure, and stable chemical properties. However, naturally produced diatomaceous earth has poor surface properties, which presents certain shortcomings in its application as an emulsifier in Pickering emulsions, thus requiring modification.
[0004] Currently, the development of diatomaceous earth-based Pickering emulsifiers for regulating emulsion-type cosmetics, especially the preparation of moisturizing facial creams using modified diatomaceous earth as an emulsifier, has not yet been carried out. Summary of the Invention
[0005] The present invention aims to obtain a safe, non-toxic, and effective emulsion-type cosmetic, and proposes a modified diatomaceous earth, a modified diatomaceous earth-based Pickering emulsion, and a method for preparing the same.
[0006] The technical solution of the present invention is as follows:
[0007] The present invention provides a modified diatomaceous earth, specifically a diatomaceous earth modified with glycidyl ether, wherein the water contact angle of the modified diatomaceous earth is 90° to 128°.
[0008] The glycidyl ether is one or a combination of at least two of allyl glycidyl ether, diglycidyl ether, isopropyl glycidyl ether, n-butyl glycidyl ether, lipoalkyl diglycidyl ether, allyl alcohol glycidyl ether, and phenyl glycidyl ether.
[0009] The present invention also provides a method for preparing the above-mentioned modified diatomaceous earth, characterized in that it specifically includes the following steps:
[0010] S1. Under a protective atmosphere, diatomaceous earth and solvent are mixed and heated to a first temperature, then glycidyl ether and acidic catalyst are added, and the mixture is heated to a second temperature to allow for complete reaction.
[0011] S2. Wash away the solvent and unreacted glycidyl ether, then filter, dry, and granulate at room temperature to obtain modified diatomaceous earth.
[0012] Preferably, the solvent in step S1 is one or a mixture of at least two of water, benzene, carbon tetrachloride, polyol, ethyl acetate, and butyl acetate; and the acidic catalyst is sulfuric acid, phosphoric acid, or a mixture of both.
[0013] Preferably, the mass ratio of diatomaceous earth, glycidyl ether, solvent and acidic catalyst in step S1 is 1:(0.1-1.0):(2-8):(1-2), more preferably 1:(0.2-0.8):(3-7):(1-1.5), and even more preferably 1:(0.4-0.6):(3-6):(1-1.2).
[0014] Preferably, in step S1, the first temperature is 50℃~60℃, the second temperature is 105℃~120℃, and the reaction time is 5h~15h, more preferably 6h~12h, and even more preferably 8h~10h.
[0015] Preferably, the drying temperature in step S2 is 95°C to 105°C.
[0016] The present invention also provides an application of the above-mentioned modified diatomaceous earth as an emulsifier for Pickering emulsions.
[0017] The present invention also provides a diatomaceous earth-based Pickering emulsion comprising the following components in parts by weight:
[0018] Phase A: 44.3 to 60.8 parts, Phase B: 14.5 to 27.5 parts, Phase C: 6.5 to 11.7 parts;
[0019] The A phase contains 40 to 55 parts water, 3 to 5 parts glycerol, 0.1 to 0.3 parts lauric acid, 0.2 to 0.5 parts potassium sorbate, and 1 to 3.5 parts of the modified diatomaceous earth as described above.
[0020] Phase B contains 5 to 8 parts stearic acid, 3 to 5 parts myristic acid, 1.5 to 3.5 parts dimethyl ether, 0.5 to 2.5 parts polyquaternium-7, 3 to 5 parts ethanol, and 1.5 to 3.5 parts butanediol;
[0021] The C phase contains 1.5 to 2.5 parts sodium hyaluronate, 1.5 to 2.0 parts acetylated sodium hyaluronate, 1.5 to 2.5 parts fibroin, 0.5 to 1.5 parts hydrolyzed silk, and 1.5 to 3.2 parts disodium EDTA.
[0022] The present invention also provides a method for preparing the above-mentioned diatomaceous earth-based Pickering emulsion, characterized by comprising the following steps:
[0023] (1) Stir and heat phase A to the dissolution and dispersion temperature, and mix thoroughly;
[0024] (2) Mix phase C evenly beforehand, stir and heat phase B separately to a specific temperature, then add phase B and phase C to phase A at the same time, emulsify with an emulsifier, and finally cool down to complete the emulsion preparation.
[0025] Preferably, the temperature for dissolving and dispersing in step (1) is 75℃~90℃; the specific temperature in step (2) is 80℃~90℃; the rotation speed of the emulsification process is 4000rpm~6000rpm; the emulsification time is 10min~20min; and the temperature after cooling is 25℃~30℃.
[0026] Compared with the prior art, the specific beneficial effects of the present invention are as follows:
[0027] 1. Diatomaceous earth has strong hydrophilicity due to the presence of silanol groups on its surface. In this invention, the silanol groups (Si-OH) on the surface are ionized by an acidic catalyst and then undergo a nucleophilic substitution reaction with the epoxy groups on the glycidyl ether. The modified diatomaceous earth exhibits enhanced hydrophobicity, with the water contact angle increasing to 90°–128°, thus improving its emulsification performance. Centrifugation tests show that the addition of modified diatomaceous earth can significantly improve the stability of the emulsion.
[0028] 2. The modified diatomaceous earth-based Pickering emulsion provided by this invention uses modified diatomaceous earth as an emulsifier, avoiding the use of organic small molecule surfactants, making it safe and non-toxic, non-irritating to the skin, and possessing excellent stability; thanks to the micro-nanoporous structure of modified diatomaceous earth, its adsorption capacity is improved, thereby achieving a better overall skin feel and oil control effect. Detailed Implementation
[0029] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.
[0030] Example 1.
[0031] Under nitrogen protection, 15.0 g of diatomaceous earth and 50.0 g of benzene were added to a reactor, and the temperature was raised to 50 °C. Then, 5.0 g of allyl glycidyl ether and 15.0 g of sulfuric acid were added dropwise to the reactor, and the reaction was carried out at 105 °C for 8 hours. After the reaction was completed, the mixture was filtered, dried, and granulated to obtain 21.5 g of modified diatomaceous earth.
[0032] The modified diatomaceous earth was subjected to a three-phase contact angle test. The specific test method is as follows:
[0033] First, the modified diatomaceous earth was pressed into tablets. Then, 2 μL of water was dropped onto the modified diatomaceous earth tablets. The contact angle was tested using a contact angle tester. The results showed that the water contact angle of the modified diatomaceous earth was 115°.
[0034] Example 2.
[0035] The amount of allyl glycidyl ether was changed to 2.0 g, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was also tested for contact angle, and the water contact angle of the modified diatomaceous earth was 93°.
[0036] Example 3.
[0037] The amount of allyl glycidyl ether was changed to 10.0 g, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was also tested for contact angle, and the water contact angle of the modified diatomaceous earth was 118°.
[0038] Example 4.
[0039] The amount of allyl glycidyl ether was changed to 15.0 g, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was also tested for contact angle, and the water contact angle of the modified diatomaceous earth was 128°.
[0040] Example 5.
[0041] Under nitrogen protection, 10.0 g of diatomaceous earth and 50.0 g of carbon tetrachloride were added to a reactor, and the temperature was raised to 60 °C. Then, 5.0 g of n-butyl glycidyl ether and 15.0 g of phosphoric acid were added dropwise to the reactor. After the addition was complete, the reaction was carried out at 120 °C for 8 hours. After the reaction was completed, the mixture was filtered, dried, and granulated to obtain 10.5 g of modified diatomaceous earth.
[0042] The modified diatomaceous earth was subjected to a three-phase contact angle test, and the results showed that the water contact angle of the modified diatomaceous earth was 125°.
[0043] Example 6.
[0044] Allyl glycidyl ether was replaced with diglycidyl ether, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was then subjected to a contact angle test, and the water contact angle of the modified diatomaceous earth was 112°.
[0045] Example 7.
[0046] Allyl glycidyl ether was replaced with isopropyl glycidyl ether, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was then subjected to a contact angle test, and the water contact angle of the modified diatomaceous earth was 118°.
[0047] Example 8.
[0048] Allyl glycidyl ether was replaced with aliphatic diglycidyl ether, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was then subjected to a contact angle test, and the water contact angle of the modified diatomaceous earth was 115°.
[0049] Example 9.
[0050] Allyl glycidyl ether was replaced with phenyl glycidyl ether, and the remaining reaction conditions were the same as in Example 1. The modified diatomaceous earth was then subjected to a contact angle test, and the water contact angle of the modified diatomaceous earth was 113°.
[0051] Example 10.
[0052] Phase A was prepared by mixing 55.0g water, 5.0g glycerol, 0.3g lauric acid, 0.5g potassium sorbate, and 2.5g modified diatomaceous earth prepared in Example 1. The mixture was heated to 85°C and stirred until homogeneous.
[0053] Mix 2.5g sodium hyaluronate (C phase), 2.0g acetylated sodium hyaluronate, 2.5g sericite, 1.5g hydrolyzed silk, and 3.2g disodium EDTA evenly.
[0054] 6.5g stearic acid, 5.0g myristic acid, 3.5g dimethyl ether, 2.5g polyquaternium-7, 5.0g ethanol and 2.5g butanediol (as phase B) were stirred and mixed evenly, and then heated to 85℃.
[0055] Phases B and C were added to phase A, and emulsified at 5000 rpm for 10 min using an emulsifier. The mixture was then cooled to 30°C to obtain diatomaceous earth-based Pickering emulsion sample 1.
[0056] Sample 1 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0057] Example 11.
[0058] The modified diatomaceous earth prepared in Example 1 was replaced with the modified diatomaceous earth in Example 6, and the remaining components were the same as in Example 10, to obtain diatomaceous earth-based Pickering emulsion sample 2.
[0059] Sample 2 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0060] Example 12.
[0061] The modified diatomaceous earth prepared in Example 1 was replaced with the modified diatomaceous earth in Example 7, and the remaining components were the same as in Example 10, to obtain diatomaceous earth-based Pickering emulsion sample 3.
[0062] Sample 3 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0063] Example 13.
[0064] The modified diatomaceous earth prepared in Example 1 was replaced with the modified diatomaceous earth in Example 8, and the remaining components were the same as in Example 10, to obtain diatomaceous earth-based Pickering emulsion sample 4.
[0065] Sample 4 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0066] Example 14.
[0067] Phase A was formed by mixing 53.7g water, 5.0g glycerol, 0.3g lauric acid, 0.5g potassium sorbate, and 3.5g modified diatomaceous earth prepared in Example 1. The mixture was heated to 85°C and stirred until homogeneous.
[0068] Mix 2.5g sodium hyaluronate (C phase), 2.0g acetylated sodium hyaluronate, 2.5g sericite, 1.5g hydrolyzed silk, and 3.0g disodium EDTA evenly.
[0069] 8.0g stearic acid, 3.0g myristic acid, 3.5g dimethyl ether, 2.5g polyquaternium-7, 5.0g ethanol and 3.5g butanediol (as phase B) were stirred and mixed evenly, and then heated to 85℃.
[0070] Phases B and C were added to phase A, and emulsified at 5000 rpm for 10 min using an emulsifier. The mixture was then cooled to 30°C to obtain diatomaceous earth-based Pickering emulsion sample 5.
[0071] Sample 5 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0072] Example 11.
[0073] Phase A was formed by mixing 55.0g water, 5.0g glycerol, 0.3g lauric acid, 0.5g potassium sorbate, and 2.5g of the modified diatomaceous earth prepared in Example 6. The mixture was heated to 85°C and stirred until homogeneous.
[0074] Mix 2.5g sodium hyaluronate (C phase), 2.0g acetylated sodium hyaluronate, 2.5g sericite, 1.5g hydrolyzed silk, and 3.2g disodium EDTA evenly.
[0075] 6.5g stearic acid, 5.0g myristic acid, 3.5g dimethyl ether, 2.5g polyquaternium-7, 5.0g ethanol and 2.5g butanediol (as phase B) were stirred and mixed evenly, and then heated to 85℃.
[0076] Phases B and C were added to phase A, and emulsified for 10 minutes at 5000 rpm using an emulsifier. The mixture was then cooled to 30°C to obtain diatomaceous earth-based Pickering emulsion sample 6.
[0077] Sample 6 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. No stratification was observed.
[0078] Comparative Example 1.
[0079] Phase A is prepared by mixing 57.5g water, 5.0g glycerol, 0.3g lauric acid, and 0.5g potassium sorbate. The mixture is heated to 85°C and stirred until homogeneous.
[0080] Mix 2.5g sodium hyaluronate (C phase), 2.0g acetylated sodium hyaluronate, 2.5g sericite, 1.5g hydrolyzed silk, and 3.2g disodium EDTA evenly.
[0081] 6.5g stearic acid, 5.0g myristic acid, 3.5g dimethyl ether, 2.5g polyquaternium-7, 5.0g ethanol and 2.5g butanediol (as phase B) were stirred and mixed evenly, and then heated to 85℃.
[0082] Phases B and C were added to phase A, and emulsified at 5000 rpm for 10 minutes using an emulsifier. The mixture was then cooled to 30°C to obtain emulsion sample 7.
[0083] Sample 7 was placed in a 10cm centrifuge tube, with a height of 7cm, and centrifuged at 3000rpm for 30min. The upper layer was 4.5cm thick.
[0084] Comparative Example 2.
[0085] Phase A was formed by mixing 57.0g water, 5.0g glycerol, 0.3g lauric acid, 0.5g potassium sorbate, and 0.5g modified diatomaceous earth prepared in Example 1. The mixture was heated to 85°C and stirred until homogeneous.
[0086] Mix 2.5g sodium hyaluronate (C phase), 2.0g acetylated sodium hyaluronate, 2.5g sericite, 1.5g hydrolyzed silk, and 3.2g disodium EDTA evenly.
[0087] 6.5g stearic acid, 5.0g myristic acid, 3.5g dimethyl ether, 2.5g polyquaternium-7, 5.0g ethanol and 2.5g butanediol (as phase B) were stirred and mixed evenly, and then heated to 85℃.
[0088] Phases B and C were added to phase A, and emulsified at 5000 rpm for 10 min using an emulsifier. The mixture was then cooled to 30°C to obtain diatomaceous earth-based Pickering emulsion sample 8.
[0089] Sample 8 was placed in a 10cm centrifuge tube, 7cm high, and centrifuged at 3000rpm for 30min. The upper layer was 2.5cm thick.
[0090] The above examples and comparative examples demonstrate that diatomaceous earth has strong hydrophilicity due to the presence of silanol groups on its surface. In this application, the silanol groups Si-OH on the surface are ionized by an acidic catalyst and then undergo a nucleophilic substitution reaction with the epoxy groups on the glycidyl ether. The modified diatomaceous earth exhibits enhanced hydrophobicity and an increased water contact angle, thus improving its emulsification performance. Centrifugation test results show that the addition of modified diatomaceous earth can significantly improve the stability of the emulsion.
Claims
1. A modified diatomaceous earth, characterized in that, The modified diatomaceous earth is specifically diatomaceous earth modified with glycidyl ether, and the water contact angle of the modified diatomaceous earth is 90°~128°. The glycidyl ether is one or a combination of at least two of allyl glycidyl ether, diglycidyl ether, isopropyl glycidyl ether, n-butyl glycidyl ether, aliphatic diglycidyl ether, allyl alcohol glycidyl ether, and phenyl glycidyl ether. The modified diatomaceous earth is prepared using the following steps: S1. Under a protective atmosphere, diatomaceous earth and solvent are mixed and heated to a first temperature, then glycidyl ether and acidic catalyst are added, and the temperature is raised to a second temperature to allow for complete reaction. S2. Wash away the solvent and unreacted glycidyl ether, then filter, dry, and granulate at room temperature to obtain modified diatomaceous earth; The acidic catalyst is sulfuric acid, phosphoric acid, or a mixture of both.
2. The modified diatomaceous earth according to claim 1, characterized in that, The solvent mentioned in step S1 is one or a mixture of at least two of the following: water, benzene, carbon tetrachloride, polyol, ethyl acetate, and butyl acetate.
3. The modified diatomaceous earth according to claim 1, characterized in that, The mass ratio of diatomaceous earth, glycidyl ether, solvent and acid catalyst in step S1 is 1:(0.1~1.0):(2~8):(1~2).
4. The modified diatomaceous earth according to claim 1, characterized in that, In step S1, the first temperature is 50℃~60℃, the second temperature is 105℃~120℃, and the reaction time is 5h~15h.
5. The modified diatomaceous earth according to claim 1, characterized in that, The drying temperature in step S2 is 95℃~105℃.
6. An application of modified diatomaceous earth as described in any one of claims 1-5, characterized in that, Used as an emulsifier in Pickering emulsions.
7. A modified diatomaceous earth-based Pickering emulsion, characterized in that, The components comprise the following parts by mass: Phase A: 44.3 to 60.8 parts, Phase B: 14.5 to 27.5 parts, Phase C: 6.5 to 11.7 parts; The A phase contains 40 to 55 parts water, 3 to 5 parts glycerol, 0.1 to 0.3 parts lauric acid, 0.2 to 0.5 parts potassium sorbate, and 1 to 3.5 parts of the modified diatomaceous earth as described in any one of claims 1-5; Phase B contains 5 to 8 parts stearic acid, 3 to 5 parts myristic acid, 1.5 to 3.5 parts dimethyl ether, 0.5 to 2.5 parts polyquaternium-7, 3 to 5 parts ethanol, and 1.5 to 3.5 parts butanediol; The C phase contains 1.5 to 2.5 parts sodium hyaluronate, 1.5 to 2.0 parts acetylated sodium hyaluronate, 1.5 to 2.5 parts fibroin, 0.5 to 1.5 parts hydrolyzed silk, and 1.5 to 3.2 parts disodium EDTA.
8. A method for preparing the modified diatomaceous earth-based Pickering emulsion as described in claim 7, characterized in that, Specifically, the steps include the following: (1) Stir and heat phase A to the dissolution and dispersion temperature, and mix thoroughly; (2) Mix phase C evenly beforehand, stir and heat phase B separately to a specific temperature, then add phase B and phase C to phase A at the same time, emulsify and cool down to complete the emulsion preparation.
9. The method for preparing the modified diatomaceous earth-based Pickering emulsion according to claim 8, characterized in that, The dissolution and dispersion temperature in step (1) is 75℃~90℃; the specific temperature in step (2) is 80℃~90℃; the rotation speed of the emulsification process is 4000rpm~6000rpm; the emulsification time is 10min~20min; and the temperature after cooling is 25℃~30℃.