Preparation method of oil-in-water or water-in-oil emulsifier based on titanium dioxide

Abstract

The invention relates to a preparation method of an oil-in-water or water-in-oil emulsifier based on titanium dioxide. The preparation method of the oil-in-water or water-in-oil emulsifier based on titanium dioxide comprises the following steps: (1) mixing and dispersing titanium dioxide and a modifier to obtain modified titanium dioxide; and (2) drying the modified titanium dioxide to obtain the emulsifier based on titanium dioxide, the particle size of the titanium dioxide in the step (1) is 100-1000 nm; the modifier is sodium silicate or a combination of silica, aluminum hydroxide and triethoxyoctyl silane, and the prepared emulsifiers are oil-in-water type emulsifiers or water-in-oil type emulsifiers respectively. According to the preparation method, titanium dioxide is taken as a raw material, an oil-in-water / water-in-oil emulsifier is obtained through modification of a special modifier, the emulsifier can improve the stability of an emulsion, meanwhile, the stickiness of a sunscreen product is reduced, the use comfort and safety are greatly improved, and a stable oil-in-water-in-oil emulsion can be formed.

Description

Technical Field

[0001] The present invention belongs to the technical field of daily chemicals, and particularly relates to a preparation method of an oil-in-water or water-in-oil emulsifier based on titanium dioxide. Background Art

[0002] Sun protection has always been an important topic in the field of cosmetics, and the stability, safety, and use comfort of sun protection products are the most important contents in the research of sun protection products. Among them, sun protection products with an emulsifying system need to add a large amount of emulsifiers and thickening and suspending stabilizers to achieve the stability of the system. The role of conventional emulsifiers is to uniformly mix the oil phase and water phase of sun protection products to form an emulsion. However, after adding conventional emulsifiers to the formula, sun protection products often have a strong sticky feeling after application. At the same time, conventional emulsifiers themselves have strong irritation, which further increases the burden on the skin. In addition, with the addition of conventional emulsifiers, the formula cost increases significantly, making it more difficult to promote sun protection products. The prior art strives to find a more mild and better-use-experience formula system to improve the product value on the premise of ensuring sun protection and skin care.

[0003] Pickering emulsion uses solid particles to replace traditional chemical emulsifiers. The solid particles form a thin film on the surface of the dispersed-phase droplets, preventing the aggregation of droplets and preparing a stable oil / water dispersed phase. When using solid particles as emulsifiers, the stability of the emulsion depends on the particle size, surface wettability of the solid particles, and the interaction between the solid particles. It can form a relatively stable thin film at the oil / water interface and has better emulsifying performance.

[0004] CN109833214A discloses a mild oil-in-water Pickering sun protection skin care product, which uses zinc oxide and sodium polyacryloyldimethyl taurate to prepare a mild oil-in-water Pickering sun protection skin care product. However, the emulsifier prepared by this method still has very limited improvement performance on the emulsion stability and skin feel comfort.

[0005] Therefore, developing a new process and technology to prepare emulsifiers to reduce the sticky feeling and irritation of sun protection products and improve the emulsion stability and use comfort has become an urgent technical problem to be solved at present. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method of an oil-in-water or water-in-oil emulsifier based on titanium dioxide. The preparation method of the emulsifier uses titanium dioxide with a particle size of 100 - 1000 nm as a raw material and is modified by a special modifier to obtain the emulsifier. The oil-in-water / water-in-oil emulsifier prepared by this method can improve the stability of the emulsion, and at the same time reduce the sticky feeling and irritation of sun protection products, greatly improving the use comfort and safety.

[0007] To achieve the object of this invention, the following technical solutions are adopted in this invention:

[0008] In a first aspect, this invention provides a preparation method of an oil-in-water or water-in-oil emulsifier based on titanium dioxide, and the preparation method includes the following steps:

[0009] (1) Mix and disperse titanium dioxide with a modifier to obtain modified titanium dioxide.

[0010] (2) After drying the modified titanium dioxide, the emulsifier based on titanium dioxide is obtained.

[0011] The particle size of the titanium dioxide in step (1) is 100 - 1000 nm.

[0012] The modifier is sodium silicate, or a combination of silica, aluminum hydroxide, and triethoxyoctylsilane with a mass ratio of 10:(3 - 8):(3 - 8). The prepared emulsifiers are respectively an oil-in-water emulsifier or a water-in-oil emulsifier.

[0013] Among them, the specific point values in 3 - 8 can be selected as 3, 4, 5, 6, 7, 8, etc., and the specific point values in 100 - 1000 nm can be selected as 100 nm, 300 nm, 500 nm, 700 nm, 900 nm, 1000 nm, etc.

[0014] Titanium dioxide is the most commonly used sunscreen raw material in sunscreen products. It has the functions of absorbing, reflecting, and converting ultraviolet rays in sunscreen products, and has good protection ability against both UVB and UVA. In this invention, appropriate modification and particle size adjustment are made to titanium dioxide particles, so that titanium dioxide has the effect of a surfactant, and while preventing ultraviolet rays, it plays a role in stabilizing the oil-water interface.

[0015] In this invention, controlling the particle size of titanium dioxide at 100 - 1000 nm can improve the dispersion stability of the prepared emulsifier in sunscreen products. At the same time, it can further improve the ultraviolet absorption effect.

[0016] In this invention, when the modifier is a combination of silica, aluminum hydroxide, and triethoxyoctylsilane with a mass ratio of 10:(3 - 8):(3 - 8), silica, aluminum hydroxide, and triethoxyoctylsilane cooperate with each other and synergistically enhance the effect, so that the prepared emulsifier based on titanium dioxide shows lipophilicity and can be well adsorbed on the oil-water interface, thereby improving the stability of the water-in-oil emulsion.

[0017] In this invention, when the modifier is only sodium silicate, the modified titanium dioxide can have a strong affinity with the water phase, the emulsifier shows hydrophilicity, and can improve the stability of the oil-in-water emulsion.

[0018] Preferably, the mass ratio of the titanium dioxide in step (1) to the mass of the modifier is 100:(1-25).

[0019] Among them, the specific point values in 1-25 can be selected as 1, 5, 10, 15, 20, 25, etc.

[0020] In the present invention, controlling the mass ratio of the titanium dioxide to the total mass of the modifier used for mixing and dispersing within the range of 100:(1-25) can improve the modification effect of the modifier on the titanium dioxide, enhance the emulsifying ability of the emulsifier, and thus further improve the stability and use comfort of the emulsion.

[0021] Preferably, before mixing the titanium dioxide and the modifier in step (1), the titanium dioxide is also surface pretreated with an oxidant.

[0022] In the present invention, the oxidant plays a role in cleaning the surface of the titanium dioxide, thereby improving the modification efficiency of the titanium dioxide.

[0023] Preferably, the oxidant includes hydrogen peroxide.

[0024] Preferably, the particle size of the titanium dioxide in step (1) is 300-500 nm, for example, it can be 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc.

[0025] In the present invention, when the particle size of the titanium dioxide is controlled within the range of 300-500 nm, the dispersion stability of the prepared emulsifier in the sunscreen product can be further improved.

[0026] Preferably, after precipitation and drying in step (2), the dried titanium dioxide is repeatedly subjected to steps (1)-(2) for 1-5 times. Repeating steps (1)-(2) for 1-5 times can better complete the modification of the titanium dioxide by the modifier and achieve a better modification effect.

[0027] Among them, the specific point values in 1-5 times can be selected as 1 time, 2 times, 3 times, 4 times, 5 times, etc.

[0028] Preferably, the temperature of the mixing in step (1) is 60-90 °C, and the mixing time is 1-20 h.

[0029] Among them, the specific point values in 60-90 °C can be selected as 60 °C, 70 °C, 80 °C, 90 °C, etc., and the specific point values in 1-20 h can be selected as 1 h, 5 h, 10 h, 15 h, 20 h, etc.

[0030] Preferably, the rotation speed of the centrifugation in step (2) is 1000 rpm-8000 rpm, and the centrifugation time is 10-50 min.

[0031] Preferably, the temperature of the drying in step (2) is 30 to 60 °C.

[0032] Among them, the specific point values in 1000 rpm to 8000 rpm can be selected as 1000 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, etc., and the specific point values in 10 to 50 min can be selected as 10 min, 20 min, 30 min, 40 min, 50 min, etc., and the specific point values in 30 to 60 °C can be selected as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, etc.

[0033] In a second aspect, the present invention provides an oil-in-water-in-oil sunscreen emulsion, and the emulsion includes an oil-in-water emulsifier prepared by the preparation method described in the first aspect, an water-in-oil emulsifier prepared by the preparation method described in the first aspect, an organic sunscreen agent, an outer oil phase and water.

[0034] The present invention uses the oil-in-water emulsifier and the water-in-oil emulsifier prepared by the preparation method described in the first aspect in the sunscreen emulsion, and further forms an oil-in-water-in-oil sunscreen emulsion with high stability, fresh skin feeling, greatly improving the use comfort while ensuring the sunscreen effect of the sunscreen emulsion, and lower cost.

[0035] Preferably, the organic sunscreen agent includes any one or a combination of at least two of diethylamino hydroxybenzoyl benzoate, ethylhexyl triazone, ethylhexyl methoxycinnamate, isoamyl p-methoxycinnamate, octocrylene, ethylhexyl salicylate or homosalate.

[0036] Preferably, the outer oil phase includes any one or a combination of at least two of dimethyldistearylammonium lithium montmorillonite, polydimethylsiloxane, triethanolamine, phenoxyethanol.

[0037] In a third aspect, the present invention provides a preparation method of an oil-in-water-in-oil sunscreen emulsion as described in the second aspect, and the preparation method includes the following steps:

[0038] (1) Mix the organic sunscreen agent, water and the oil-in-water emulsifier, and obtain an oil-in-water emulsion through high-speed homogenization and high-pressure homogenization.

[0039] (2) Mix the outer oil phase with the water-in-oil emulsifier, then mix with the oil-in-water emulsion, and obtain an oil-in-water-in-oil sunscreen emulsion through high-speed homogenization.

[0040] Preferably, the rotation speed of the high-speed homogenization in step (1) is 1500 to 2500 rpm, and the time is 15 to 30 min.

[0041] Preferably, the pressure of the high-pressure homogenization in step (1) is 800-1600 bar, and the number of cycles is 1-3 times.

[0042] Preferably, the rotation speed of the high-speed homogenization in step (2) is 800-1200 rpm, and the time is 10-40 min.

[0043] Among them, specific point values within 1500-2500 rpm can be selected as 1500 rpm, 1800 rpm, 2100 rpm, 2500 rpm, etc.; specific point values within 800-1200 rpm can be selected as 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, etc.; specific point values within 800-1600 bar can be selected as 800 bar, 1000 bar, 1200 bar, 1400 bar, 1600 bar, etc.; specific point values within 1-3 times can be selected as 1 time, 2 times, 3 times, etc.; specific point values within 15-30 min can be selected as 15 min, 20 min, 25 min, 30 min, etc.; specific point values within 10-40 min can be selected as 10 min, 20 min, 30 min, 40 min, etc.

[0044] The numerical ranges described in the present invention not only include the above-listed point values, but also include any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The preparation method of the oil-in-water or water-in-oil emulsifier based on titanium dioxide developed by the present invention: when the modifier is a combination of silica, aluminum hydroxide, and triethoxysilane with a mass ratio of 10:(3-8):(3-8), silica, aluminum hydroxide, and triethoxysilane cooperate with each other and synergistically enhance the effect, making the prepared titanium dioxide-based emulsifier lipophilic and capable of being well adsorbed at the oil-water interface, and an oil-in-water emulsifier with good stability and emulsification effect is prepared; when the modifier is only sodium silicate, the modified titanium dioxide can have a strong affinity with the water phase, the emulsifier is hydrophilic, and a water-in-oil emulsifier with good stability and emulsification effect is prepared.

[0047] The water-in-oil / water-in-oil emulsifier prepared by the preparation method developed by the present invention can improve the stability of the emulsion, reduce the sticky feeling during the use of the emulsion product at the same time, has low irritation, greatly improves the use comfort and safety, and has lower cost because no more expensive surfactants are used. Specific Embodiments

[0048] To further illustrate the technical means and effects adopted by the present invention, the following further describes the technical solution of the present invention in conjunction with the preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0049] In the following embodiments, the sources of each component / raw material are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] Example 1-1

[0054] This example provides an oil-in-water emulsifier, which is prepared by the following method:

[0055] (1) Take titanium dioxide particles with a particle size of 400 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 10 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 10 h, then unseal and dry in an oven at 50 °C to obtain titanium dioxide powder;

[0056] (2) Add an aqueous solution of sodium silicate to the titanium dioxide powder, mix and disperse at 80 °C (ultrasonically disperse for 10 min, stir magnetically for 10 h). The mass ratio of titanium dioxide to sodium silicate in the aqueous solution of sodium silicate is 100:15 to obtain modified titanium dioxide;

[0057] (3) Let the modified titanium dioxide stand, centrifuge at a high speed of 4000 rpm for 30 min, remove the supernatant, and dry the lower precipitate in an oven at 45 °C;

[0058] (4) Repeat steps (2) to (3) for the dried titanium dioxide 3 times, and prepare a titanium dioxide oil-in-water emulsifier after sufficient grinding.

[0059] Example 1-2

[0060] This example provides a water-in-oil emulsifier, which is prepared by the following method:

[0061] (1) Take titanium dioxide particles with a particle size of 400 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 10 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 10 h, then unseal and dry in an oven at 50 °C to obtain titanium dioxide powder; Mix silica, aluminum hydroxide, and triethoxyoctylsilane in a mass ratio of 10:6:6 to obtain a modifier mixture;

[0062] (2) Add the modifier mixture to the dried titanium dioxide powder, and mix and disperse at 80 °C (ultrasonic dispersion for 10 min, magnetic stirring for 10 h). The total mass ratio of the titanium dioxide powder to the modifier mixture is 100:15 to obtain modified titanium dioxide;

[0063] (3) Place the modified titanium dioxide in an oven and dry it at 45 °C;

[0064] (4) Repeat steps (2) to (3) for the dried modified titanium dioxide 3 times, and after sufficient grinding, prepare a water-in-oil type titanium dioxide emulsifier.

[0065] Example 2-1

[0066] This example provides an oil-in-water type emulsifier, which is prepared by the following method:

[0067] (1) Take titanium dioxide particles with a particle size of 300 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 3 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 3 h, then unseal and place it in an oven to dry at 55 °C to obtain titanium dioxide powder;

[0068] (2) Add an aqueous solution of sodium silicate to the titanium dioxide powder, and mix and disperse at 60 °C (ultrasonic dispersion for 3 min, magnetic stirring for 2 h). The mass ratio of titanium dioxide to sodium silicate in the aqueous solution of sodium silicate is 100:1 to obtain modified titanium dioxide;

[0069] (3) Let the modified titanium dioxide stand still, centrifuge at a high speed of 6000 rpm for 50 min, remove the supernatant, and place the lower layer precipitate in an oven to dry at 60 °C;

[0070] (4) Repeat steps (2) to (3) for the dried titanium dioxide 4 times, and after sufficient grinding, prepare a water-in-oil type titanium dioxide emulsifier.

[0071] Example 2-2

[0072] This example provides a water-in-oil type emulsifier, which is prepared by the following method:

[0073] (1) Take titanium dioxide particles with a particle size of 300 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 3 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 3 h, then unseal and place it in an oven to dry at 40 °C to obtain titanium dioxide powder; Mix silica, aluminum hydroxide and triethoxyoctylsilane in a mass ratio of 10:3:3 to obtain a modifier mixture;

[0074] (2) Add the modifier mixture to the dried titanium dioxide powder and mix and disperse it at 60°C (ultrasonic dispersion for 3 min and magnetic stirring for 2 h). The total mass ratio of the titanium dioxide powder to the modifier mixture is 100:1 to obtain modified titanium dioxide;

[0075] (3) Place the modified titanium dioxide in an oven and dry it at 60°C;

[0076] (4) Repeat steps (2) to (3) for the dried modified titanium dioxide 4 times, and prepare a water-in-oil type emulsifier of titanium dioxide after sufficient grinding.

[0077] Example 3-1

[0078] This example provides an oil-in-water type emulsifier, which is prepared by the following method:

[0079] (1) Take titanium dioxide particles with a particle size of 500 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 20 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 20 h, then unseal and place it in an oven to dry at 60°C to obtain titanium dioxide powder;

[0080] (2) Add an aqueous solution of sodium silicate to the titanium dioxide powder and mix and disperse it at 90°C (ultrasonic dispersion for 20 min and magnetic stirring for 15 h). The mass ratio of titanium dioxide to sodium silicate in the aqueous solution of sodium silicate is 100:25 to obtain modified titanium dioxide;

[0081] (3) Let the modified titanium dioxide stand, centrifuge at 2000 rpm for 10 min, remove the supernatant, and place the lower precipitate in an oven to dry at 30°C;

[0082] (4) Repeat steps (2) to (3) for the dried titanium dioxide 1 time, and prepare a water-in-oil type emulsifier of titanium dioxide after sufficient grinding.

[0083] Example 3-2

[0084] This example provides a water-in-oil type emulsifier, which is prepared by the following method:

[0085] (1) Take titanium dioxide particles with a particle size of 500 nm, pour them into an appropriate amount of hydrogen peroxide solution, ensure that the hydrogen peroxide solution completely submerges the titanium dioxide particles, ultrasonically disperse for 20 min, seal the ultrasonically dispersed solution, place it in the dark and stir magnetically for 20 h, then unseal and place it in an oven to dry at 70°C to obtain titanium dioxide powder; Mix silica, aluminum hydroxide and triethoxyoctylsilane in a mass ratio of 10:8:8 to obtain a modifier mixture;

[0086] (2) Add the modifier mixture to the dried titanium dioxide powder, and mix and disperse at 90 °C (ultrasonic dispersion for 20 min and magnetic stirring for 15 h). The total mass ratio of the titanium dioxide powder to the modifier mixture is 100:25 to obtain modified titanium dioxide;

[0087] (3) Place the modified titanium dioxide in an oven and dry it at 30 °C;

[0088] (4) Repeat steps (2) to (3) for the dried modified titanium dioxide once, and prepare a water-in-oil type emulsifier of titanium dioxide after sufficient grinding.

[0089] Example 4-1

[0090] This example provides an oil-in-water type emulsifier, which is only different from Example 1-1 in that the particle size of the titanium dioxide particles in step (1) is adjusted to 200 nm, and the remaining steps are the same as those in Example 1.

[0091] Example 4-2

[0092] This example provides a water-in-oil type emulsifier, which is only different from Example 1-2 in that the particle size of the titanium dioxide particles in step (1) is adjusted to 200 nm, and the remaining steps are the same as those in Example 1.

[0093] Example 5-1

[0094] This example provides an oil-in-water type emulsifier, which is only different from Example 1-1 in that the particle size of the titanium dioxide particles in step (1) is adjusted to 600 nm, and the remaining steps are the same as those in Example 1.

[0095] Example 5-2

[0096] This example provides a water-in-oil type emulsifier, which is only different from Example 1-2 in that the particle size of the titanium dioxide particles in step (1) is adjusted to 600 nm, and the remaining steps are the same as those in Example 1.

[0097] Example 6-1

[0098] This example provides an oil-in-water type emulsifier, which is only different from Example 1-1 in that step (4) of repeated modification is not carried out. That is, after drying in step (3), a water-in-oil type emulsifier of titanium dioxide is obtained after sufficient grinding, and the remaining steps are the same as those in Example 1.

[0099] Example 6-2

[0100] This embodiment provides a water-in-oil emulsifier, which is only different from Embodiments 1-2 in that the repeated modification in step (4) is not carried out. That is, after drying in step (3), the titanium dioxide water-in-oil emulsifier is obtained after sufficient grinding, and the remaining steps are the same as those in Embodiment 1.

[0101] Example 7-1

[0102] This embodiment provides an oil-in-water emulsifier, which is only different from Embodiment 1-1 in that the mass ratio of sodium silicate in the aqueous solution of sodium silicate and titanium dioxide powder in step (2) is adjusted to 100:0.5, and the remaining steps are the same as those in Embodiment 1.

[0103] Example 7-2

[0104] This embodiment provides a water-in-oil emulsifier, which is only different from Embodiment 1-2 in that the total mass ratio of titanium dioxide powder and modifier mixture in step (2) is adjusted to 100:0.5, and the remaining steps are the same as those in Embodiment 1.

[0105] Example 8-1

[0106] This embodiment provides an oil-in-water emulsifier, which is only different from Embodiment 1-1 in that the mass ratio of sodium silicate in the aqueous solution of sodium silicate and titanium dioxide powder in step (2) is adjusted to 100:30, and the remaining steps are the same as those in Embodiment 1.

[0107] Example 8-2

[0108] This embodiment provides a water-in-oil emulsifier, which is only different from Embodiment 1-2 in that the total mass ratio of titanium dioxide powder and modifier mixture in step (2) is adjusted to 100:30, and the remaining steps are the same as those in Embodiment 1.

[0109] Comparative Example 1-1

[0110] This comparative example provides an oil-in-water emulsifier, which is only different from Embodiment 1-1 in that the particle size of titanium dioxide particles in step (1) is adjusted to 50 nm, and the remaining steps are the same as those in Embodiment 1-1.

[0111] Comparative Example 1-2

[0112] This comparative example provides a water-in-oil emulsifier, which is only different from Embodiment 1-2 in that the particle size of titanium dioxide particles in step (1) is adjusted to 50 nm, and the remaining steps are the same as those in Embodiment 1-2.

[0113] Comparative Example 2-1

[0114] This comparative example provides an oil-in-water emulsifier, which is different from Example 1-1 only in that the particle size of titanium dioxide particles in step (1) is adjusted to 1200 nm, and the remaining steps are the same as those in Example 1-1.

[0115] Comparative Example 2-2

[0116] This comparative example provides a water-in-oil emulsifier, which is different from Example 1-2 only in that the particle size of titanium dioxide particles in step (1) is adjusted to 1200 nm, and the remaining steps are the same as those in Example 1-2.

[0117] Comparative Example 3

[0118] This comparative example provides a water-in-oil emulsifier, which is different from Example 1-2 only in that the modifier mixture in step (1) is adjusted to silica and aluminum hydroxide with a mass ratio of 10:6, and the remaining steps are the same as those in Example 1-2.

[0119] Comparative Example 4

[0120] This comparative example provides a water-in-oil emulsifier, which is different from Example 1-2 only in that the modifier mixture in step (1) is adjusted to silica and triethoxyoctylsilane with a mass ratio of 10:6, and the remaining steps are the same as those in Example 1-2.

[0121] Comparative Example 5

[0122] This comparative example provides a water-in-oil emulsifier, which is different from Example 1-2 only in that the modifier mixture in step (1) is adjusted to aluminum hydroxide and triethoxyoctylsilane with a mass ratio of 6:6, and the remaining steps are the same as those in Example 1-2.

[0123] Application Example 1

[0124] This application example provides an oil-in-water-in-oil sunscreen lotion, and its preparation raw materials are shown in the following table:

[0125] Table 2

[0126]

[0127] The preparation method of this oil-in-water-in-oil sunscreen lotion is as follows:

[0128] (1) Mix the organic sunscreen agent, water and the oil-in-water emulsifier, homogenize at a rotation speed of 2000 rpm for 25 min, and homogenize 2 times at a pressure of 1200 bar to obtain an oil-in-water emulsion;

[0129] (2) Mix lithium montmorillonite dimethyldistearylammonium, polydimethylsiloxane, triethanolamine, phenoxyethanol and a water-in-oil emulsifier, then mix with the oil-in-water emulsion obtained in step (1), stir and disperse at low speed, and then homogenize at a speed of 1000 rpm for 20 min to obtain an oil-in-water-in-oil sunscreen emulsion.

[0130] Application Example 2

[0131] This application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 2-1 and the oil-in-water emulsifier prepared in Example 2-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0132] Application Example 3

[0133] This application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 3-1 and the oil-in-water emulsifier prepared in Example 3-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0134] Application Example 4

[0135] This application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 4-1 and the oil-in-water emulsifier prepared in Example 4-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0136] Application Example 5

[0137] This application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 5-1 and the oil-in-water emulsifier prepared in Example 5-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0138] Application Example 6

[0139] This application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 6-1 and the oil-in-water emulsifier prepared in Example 6-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0140] Application Example 7

[0141] This application example provides an oil-in-water-in-oil type sunscreen emulsion, the difference from Application Example 1 is only that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 7-1 and the oil-in-water emulsifier prepared in Example 7-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0142] Application Example 8

[0143] This application example provides an oil-in-water-in-oil type sunscreen emulsion, the difference from Application Example 1 is only that the water-in-oil emulsifier and the oil-in-water emulsifier are respectively replaced with the water-in-oil emulsifier prepared in Example 8-1 and the oil-in-water emulsifier prepared in Example 8-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0144] Application Example 9

[0145] This application example provides an oil-in-water-in-oil type sunscreen emulsion, and its preparation raw materials are shown in the following table:

[0146] Table 3

[0147]

[0148]

[0149] The preparation method of this oil-in-water-in-oil type sunscreen emulsion is as follows:

[0150] (1) Mix the organic sunscreen agent, water and the water-in-oil emulsifier, homogenize at a speed of 1500 rpm for 15 minutes, and homogenize 3 times at a pressure of 800 bar to obtain a water-in-oil emulsion;

[0151] (2) Mix lithium magnesium aluminosilicate, polydimethylsiloxane, triethanolamine, phenoxyethanol and the oil-in-water emulsifier, then mix with the water-in-oil emulsion obtained in step (1), stir and disperse at low speed, and then homogenize at a speed of 800 rpm for 10 minutes to obtain an oil-in-water-in-oil type sunscreen emulsion.

[0152] Application Example 10

[0153] This application example provides an oil-in-water-in-oil type sunscreen emulsion, and its preparation raw materials are shown in the following table:

[0154] Table 4

[0155]

[0156]

[0157] The preparation method of this oil-in-water-in-oil type sunscreen emulsion is as follows:

[0158] (1) Mix the organic sunscreen, water, and oil-in-water emulsifier, homogenize at a rotation speed of 2500 rpm for 30 min, and homogenize once at a pressure of 1600 bar to obtain an oil-in-water emulsion;

[0159] (2) Mix lithium magnesium stearate montmorillonite, polydimethylsiloxane, triethanolamine, phenoxyethanol, and water-in-oil emulsifier, then mix with the oil-in-water emulsion obtained in step (1), stir and disperse at low speed, and then homogenize at a rotation speed of 1200 rpm for 40 min to obtain an oil-in-water-in-oil sunscreen emulsion.

[0160] Comparative Application Example 1

[0161] This comparative application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the oil-in-water emulsifier and the water-in-oil emulsifier are respectively replaced with the oil-in-water emulsifier prepared in Comparative Example 1-1 and the water-in-oil emulsifier prepared in Comparative Example 1-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0162] Comparative Application Example 2

[0163] This comparative application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the oil-in-water emulsifier and the water-in-oil emulsifier are respectively replaced with the oil-in-water emulsifier prepared in Comparative Example 2-1 and the water-in-oil emulsifier prepared in Comparative Example 2-2, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0164] Comparative Application Example 3

[0165] This comparative application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier is replaced with the water-in-oil emulsifier prepared in Comparative Example 3, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0166] Comparative Application Example 4

[0167] This comparative application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier is replaced with the water-in-oil emulsifier prepared in Comparative Example 4, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0168] Comparative Application Example 5

[0169] This comparative application example provides an oil-in-water-in-oil sunscreen emulsion, which is only different from Application Example 1 in that the water-in-oil emulsifier is replaced with the water-in-oil emulsifier prepared in Comparative Example 5, and the weight parts of each raw material and the preparation method of the emulsion are the same as those in Application Example 1.

[0170] Comparative Application Example 6

[0171] This comparative application example provides an oil-in-water-in-oil sunscreen lotion, which is only different from Application Example 1 in that the water-in-oil emulsifier is replaced with an equal mass of a conventional water-in-oil emulsifier: carbomer, and the oil-in-water emulsifier is replaced with an equal mass of a conventional oil-in-water emulsifier: lauryl PEG-10 tris(trimethylsiloxy)silylethyl polydimethylsiloxane. The remaining raw materials and preparation method are the same as those in Application Example 1.

[0172] Comparative Application Example 7

[0173] This comparative application example provides an oil-in-water-in-oil sunscreen lotion, which is only different from Application Example 1 in that the water-in-oil emulsifier is replaced with an equal mass of a conventional water-in-oil emulsifier: polysorbate-20, and the oil-in-water emulsifier is replaced with an equal mass of a conventional oil-in-water emulsifier: magnesium stearate. The remaining raw materials and preparation method are the same as those in Application Example 1.

[0174] Test Example 1

[0175] Test the stability:

[0176] Conduct low temperature (-5°C ± 2°C), high temperature (45°C ± 2°C), and high-low temperature cycle (first high temperature for 24 h, then low temperature for 24 h, regarded as one cycle) tests on the sunscreen lotion samples of Application Examples 1-10 and Comparative Application Examples 1-7 respectively. The test duration is 30 days. After the test, observe whether there are abnormal phenomena such as discoloration, delamination, precipitation, etc. in the sunscreen lotion samples. The results are shown in Table 5.

[0177] Table 5

[0178] Sample Low-temperature test High-temperature test High-low temperature cycle test Application Example 1 No abnormality No abnormality No abnormality Application Example 2 No abnormality No abnormality No abnormality Application Example 3 No abnormality No abnormality No abnormality Application Example 4 No abnormality No abnormality No abnormality Application Example 5 No abnormality No abnormality No abnormality Application Example 6 No abnormality No abnormality No abnormality Application Example 7 No abnormality No abnormality No abnormality Application Example 8 No abnormality No abnormality No abnormality Application Example 9 No abnormality No abnormality No abnormality Application Example 10 No abnormality No abnormality No abnormality Comparative Application Example 1 No abnormality Color change Color change Comparative Application Example 2 No abnormality Color change Color change Comparative Application Example 3 No abnormality Layering Layering Comparative Application Example 4 No abnormality Color change Color change and layering Comparative Application Example 5 No abnormality Color change Color change and layering Comparative Application Example 6 No abnormality No abnormality No abnormality Comparative Application Example 7 No abnormality No abnormality No abnormality

[0179] Test Example 2

[0180] Evaluation of skin feel:

[0181] Select 170 volunteers aged 18-60 who have passed the sensory test training to conduct product sensory evaluation tests. Divide the volunteers into 17 groups evenly, with 10 people in each group. After resting for 1 h in an independent environment with a constant temperature of 22 ± 1°C and a relative humidity of 50 ± 5%, use the sunscreen lotions provided by Application Examples 1-10 and Comparative Application Examples 1-7 for testing respectively.

[0182] Scoring system: The score is from 1 to 10. Each volunteer evaluates the spreadability and freshness of the product according to the scoring criteria shown in Table 6; after scoring, take the average value of each sample. The higher the score, the stronger the characteristic of the item index. The test results are shown in Table 7.

[0183] Table 6

[0184] Sub-item Spreading property Freshness degree 9 - 10 points Very easy Extremely fresh 7 - 8 points Easy Good 5 - 6 points Average Average 3 - 4 points Relatively difficult Sticky 1 - 2 points Extremely difficult Extremely sticky

[0185] Table 7

[0186]

[0187]

[0188] Test Example 3

[0189] Sun protection factor test:

[0190] Refer to the method for determining the sun protection factor (SPF value) of sunscreen cosmetics in the Cosmetics Safety and Technology Specifications (2015 Edition) to conduct the sun protection factor test.

[0191] Select the same 170 volunteers as in Test Example 2, divide them into 17 groups on average, with 10 people in each group. Select an irradiation area on the back skin of the subjects, take 5 points and irradiate them with different doses of ultraviolet light. The shortest irradiation time when erythema appears on the skin is the minimum erythema dose (MED) of the normal skin of the subject. Apply the test product to the skin of the subjects, weigh the sample according to the dosage of (2.00 ± 0.05) mg / cm 2 , evenly coat the sample in the test area. After waiting for 20 minutes, take 5 points and irradiate them with different doses of ultraviolet light. The shortest irradiation time when erythema appears on the skin is the MED of the skin of the subject under the protection of the product. The SPF value of the sample for a single subject is calculated by the following formula, and the test results are the average values of each group:

[0192] Individual SPF = MED of the skin protected by the sample / MED of the unprotected skin. The test results are shown in Table 8:

[0193] Table 8

[0194] Sample SPF value Application Example 1 45.8 Application Example 2 43.5 Application Example 3 44.9 Application Example 4 42.2 Application Example 5 42.1 Application Example 6 40.6 Application Example 7 41.7 Application Example 8 40.5 Application Example 9 44.3 Application Example 10 43.8 Comparative Application Example 1 31.5 Comparative Application Example 2 32.7 Comparative Application Example 3 30.9 Comparative Application Example 4 28.2 Comparative Application Example 5 31.3 Comparative Application Example 6 29.7 Comparative Application Example 7 30.4

[0195] Test Example 4

[0196] Irritation test:

[0197] Select 85 of the same volunteers as in Test Example 2, divide them into 17 groups on average, with 5 people in each group, and conduct the following safety evaluation tests:

[0198] Add the sunscreen lotion products prepared in each application example to the patch test device respectively, and apply it to the inner side of the forearm of the volunteers with a low-sensitization tape. Gently press with the palm to make it evenly adhere to the skin. After waiting for 24 hours, remove the patch test device, and start timing after the indentation disappears. Observe the skin condition of the test area of the volunteers at 30 minutes and 24 hours respectively according to the criteria shown in Table 9. The average value of the skin reaction score level of each group of subjects is taken, and the statistical results are shown in Table 10.

[0199] Table 9

[0200]

[0201] The test results are shown in Table 10:

[0202] Table 10

[0203]

[0204]

[0205] From the test data in Tables 5 - 10 above, it can be seen that the emulsifier prepared by the present invention has low irritation, and can improve the stability and skin feel comfort of the emulsion product while maintaining the sun protection effect.

[0206] From the data comparison between Application Example 1 and Comparative Application Examples 6 - 7, it can be seen that compared with traditional emulsifiers, the emulsifier prepared by the present invention can significantly improve the spreading property and freshness of the emulsion, reduce irritation, and greatly improve the use comfort of the product.

[0207] From the data comparison between Application Example 1 and Comparative Application Examples 1 - 2, it can be seen that during the preparation process of the emulsifier, when the particle size range of titanium dioxide particles is outside 100 - 1000 nm, the modification effect of the modifier on titanium dioxide is poor, thus affecting the emulsifying ability of the prepared emulsifier.

[0208] From the data comparison between Application Example 1 and Comparative Application Examples 3 - 5, it can be seen that during the preparation process of the water-in-oil emulsifier, when any one of silica, aluminum hydroxide, or triethoxyoctylsilane is missing from the modifier, the emulsifying ability of the prepared water-in-oil emulsifier decreases, thus affecting the stability and use comfort of the emulsion product.

[0209] From the data comparison between Application Example 1 and Application Examples 4 - 5, it can be seen that when the particle size of titanium dioxide particles is controlled within the range of 300 - 500 nm, the emulsifying ability of the prepared emulsifier is better, and the stability and use comfort of the emulsion can be further improved.

[0210] From the data comparison between Application Example 1 and Application Example 6, it can be seen that when the number of times of mixing and dispersing titanium dioxide particles with the modifier is controlled within 2 - 5 times, the modification effect of the modifier on titanium dioxide can be improved, and the emulsifying ability of the emulsifier can be improved, thereby further enhancing the stability and use comfort of the emulsion.

[0211] From the data comparison between Application Example 1 and Application Examples 7 - 8, it can be seen that when the mass ratio of titanium dioxide to the total mass of the modifier used for mixing and dispersing is controlled within the range of 100:(1 - 25), the modification effect of the modifier on titanium dioxide can be improved, and the emulsifying ability of the emulsifier can be improved, thereby further enhancing the stability and use comfort of the emulsion.

[0212] The applicant declares that the technical solution of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

[0213] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0214] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any appropriate manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination manners.

Claims

1. A method for preparing an oil-in-water or water-in-oil emulsifier based on titanium dioxide, characterized in that: The preparation method comprises the following steps: (1) mixing and dispersing titanium dioxide and a modifier to obtain modified titanium dioxide; (2) drying the modified titanium dioxide to obtain the titanium dioxide-based emulsifier; The particle size of the titanium dioxide in step (1) is 100 to 1000 nm; The modifier is sodium silicate, or a combination of silica, aluminum hydroxide and triethoxyoctylsilane in a mass ratio of 10:(3-8):(3-8), and the prepared emulsifier is an oil-in-water emulsifier or an oil-in-water emulsifier.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the titanium dioxide to the modifier in step (1) is 100:(1-25).

3. The preparation method according to claim 1 or 2, characterized in that: Before the titanium dioxide and the modifier are mixed in step (1), the titanium dioxide surface is pretreated by using an oxidant; Preferably, the oxidizing agent comprises hydrogen peroxide.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The particle size of the titanium dioxide in step (1) is 300 to 500 nm.

5. The preparation method according to any one of claims 1 to 4, characterized in that: After the precipitate in step (2) is dried, the method further comprises repeating steps (1) to (2) for 1 to 5 times with the dried titanium dioxide.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The mixing temperature in step (1) is 60 to 90° C. and the mixing time is 1 to 20 hours; Preferably, the centrifugal speed in step (2) is 1000-8000 rpm, and the centrifugal time is 10-50 min; Preferably, the drying temperature in step (2) is 30-60°C.

7. An oil-in-water-in-oil type sunscreen lotion, characterized in that: The emulsion comprises an oil-in-water emulsifier prepared by the preparation method of claim 1, an oil-in-water emulsifier prepared by the preparation method of claim 1, an organic sunscreen, an outer oil phase and water.

8. The oil-in-water-in-oil sunscreen lotion according to claim 7, characterized in that: The organic sunscreen includes any one or a combination of at least two of diethylaminohydroxybenzoyl hexyl benzoate, ethylhexyl triazone, ethylhexyl methoxycinnamate, isoamyl p-methoxycinnamate, octocrylene, ethylhexyl salicylate or homosalate; Preferably, the outer oil phase comprises any one of disteardimethylammonium hectorite, polydimethylsiloxane, triethanolamine, and phenoxyethanol, or a combination of at least two thereof.

9. A method for preparing the oil-in-water-in-oil type sunscreen emulsion according to claim 7 or 8, characterized in that: The preparation method comprises the following steps: (1) mixing an organic sunscreen, water and an oil-in-water emulsifier, and subjecting the mixture to high-speed homogenization and high-pressure homogenization to obtain an oil-in-water emulsion; (2) The outer oil phase is mixed with a water-in-oil emulsifier, and then mixed with an oil-in-water emulsion, and subjected to high-speed homogenization to obtain an oil-in-water-in-oil sunscreen emulsion.

10. The method for preparing the oil-in-water-in-oil type sunscreen emulsion according to claim 9, characterized in that: The speed of the high-speed homogenization in step (1) is 1500-2500 rpm, and the time is 15-30 min; Preferably, the pressure of the high-pressure homogenization in step (1) is 800 to 1600 bar, and the number of cycles is 1 to 3 times; Preferably, the speed of the high-speed homogenization in step (2) is 800 to 1200 rpm, and the time is 10 to 40 minutes.

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