A titanium dioxide aqueous dispersion, its preparation method and application

Abstract

This invention provides a titanium dioxide aqueous dispersion, its preparation method, and its application, belonging to the field of cosmetic technology. The titanium dioxide aqueous dispersion of this invention comprises the following components in parts by weight: 60-75 parts nano-titanium dioxide, 10-25 parts polyol, 1-5 parts polysaccharide polymer, and 10-20 parts water; wherein the polysaccharide polymer includes propylene glycol alginate. This invention adds polyol and polysaccharide polymer to the titanium dioxide aqueous dispersion, improving the dispersibility of nano-titanium dioxide, thereby enhancing the stability of cosmetics containing the nano-titanium dioxide aqueous dispersion, especially the stability, skin feel, and sun protection effect of water-in-oil sunscreens.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology, specifically relating to a titanium dioxide aqueous dispersion, its preparation method, and its application. Background Technology

[0002] Nano titanium dioxide, as an inorganic sunscreen agent, not only has the ability to absorb ultraviolet rays, but also to scatter and refract ultraviolet rays. Nano titanium dioxide has a shielding effect on ultraviolet rays of all wavelengths. At the same time, titanium dioxide has excellent photostability and thermal stability, and is non-toxic and odorless. Therefore, it is widely used in sunscreen skin care products.

[0003] However, the use of nano-titanium dioxide presents several problems: for example, adding high doses of nano-titanium dioxide to oil-in-water sunscreens can cause a white cast during application. Furthermore, nano-titanium dioxide has high surface energy, making it prone to powder aggregation in cosmetics, resulting in a rough surface and decreased stability in oil-in-water sunscreens. To improve this, surface modifiers are typically used to coat the surface of titanium dioxide, improving its dispersibility in water and oil media, allowing for uniform dispersion. Oil-in-water sunscreens have a pH of 6-7. In a weakly acidic environment, the negative charge on the surface of the modified titanium dioxide decreases, leading to a thinner electric double layer and reduced repulsive forces between particles. This causes the modified titanium dioxide to agglomerate, and over time, the aggregation increases, resulting in surface roughness, a jelly-like texture, and other instability in the oil-in-water sunscreen. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a titanium dioxide aqueous dispersion, its preparation method and application, wherein the titanium dioxide aqueous dispersion has high dispersibility.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is as follows: This invention provides a titanium dioxide aqueous dispersion comprising the following components in parts by weight: 60-75 parts nano titanium dioxide, 10-25 parts polyol, 1-5 parts polysaccharide polymer, and 10-20 parts water; wherein the polysaccharide polymer includes propylene glycol alginate.

[0006] In some embodiments, the polysaccharide polymer further includes at least one of the following: Carrageenan extract, sodium carrageenan, gum arabic, arabar gum, and carboxymethyl chitosan.

[0007] In some embodiments, the polysaccharide polymer is propylene glycol alginate and chondrus crispus extract, with a mass ratio of propylene glycol alginate to chondrus crispus extract of 7:1 to 1:3.

[0008] In some embodiments, the polyol is at least one selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, pentylene glycol, hexanediol, and methylpropanediol.

[0009] In some embodiments, the polyol is dipropylene glycol and methyl propylene glycol, with a mass ratio of 1.5-4.

[0010] In some embodiments, the nano-titanium dioxide is modified with a surface treatment agent, which is at least one selected from silane coupling agent, hydrogenated polydimethylsiloxane, silicon dioxide, aluminum hydroxide, and amino acids.

[0011] In a second aspect, a method for preparing the titanium dioxide aqueous dispersion is provided, comprising the following steps: mixing polyol and polysaccharide polymer evenly, adding water and heating to 60-80℃ and stirring until transparent, then adding nano-titanium dioxide, homogenizing at a speed of 5000-8000 r / min for 3-5 min, stirring and cooling to room temperature to obtain the titanium dioxide aqueous dispersion.

[0012] Thirdly, the application of the titanium dioxide dispersion in cosmetics is provided.

[0013] Fourthly, a cosmetic product is provided, comprising the titanium dioxide aqueous dispersion, wherein the titanium dioxide aqueous dispersion comprises 6-15% by mass in the cosmetic product.

[0014] In some embodiments, the cosmetic is a sunscreen lotion, and the sunscreen lotion comprises the following components in weight percentage: 6-15% titanium dioxide aqueous dispersion, 5-15% organic sunscreen agent, 5-30% oil, 0.5-5% emulsifier, 0.1-5% skin conditioning agent, 0.1-20% moisturizer, 0.05-5% rheology modifier, 0.05-3% antioxidant, 0.1-0.6% preservative, 0.05-5% pH adjuster, 0.01-1% fragrance, and the balance being water.

[0015] Compared with the prior art, the beneficial effects of this disclosure are as follows: In this invention, polyols and polysaccharide polymers are added to the titanium dioxide aqueous dispersion. The hydroxyl groups on the surface of nano-titanium dioxide and the hydroxyl groups of the polysaccharide polymer interact through van der Waals forces, causing the nano-titanium dioxide to be adsorbed on the surface of the polysaccharide polymer, which enhances the repulsive force between nano-titanium dioxide particles and reduces the aggregation of nano-titanium dioxide. In addition, under the condition of water presence, the polyol and polysaccharide polymer form supramolecular structures that interact with each other by hydrogen bonds and van der Waals forces, which significantly improves the repulsive force between nano-titanium dioxide particles and further improves the dispersibility of nano-titanium dioxide, thereby improving the stability of cosmetics containing nano-titanium dioxide aqueous dispersions, especially the stability, skin feel and sun protection effect of water-in-oil sunscreen products. Attached Figure Description

[0016] Figure 1 This is a diagram showing the dispersion effect of the titanium dioxide aqueous dispersion in water in Example 1 of the present invention;

[0017] Figure 2 This is a diagram showing the dispersion effect of the titanium dioxide aqueous dispersion in oil in Example 1 of the present invention;

[0018] Figure 3 This is a diagram showing the appearance and stability of the titanium dioxide aqueous dispersion in Example 1 of the present invention.

[0019] Figure 4 This is a diagram showing the appearance and stability of the titanium dioxide aqueous dispersion of Comparative Example 1 of the present invention. Detailed Implementation

[0020] To facilitate understanding of this disclosure, a more complete description will be provided below. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0021] As used in this article:

[0022] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0023] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0024] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1-5” is disclosed, the described range should be interpreted as including ranges “1-4”, “1-3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0025] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0026] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0027] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0028] To address the problem that high-dose nano-titanium dioxide tends to aggregate in oil-in-water sunscreens in existing technologies, leading to reduced stability of these products.

[0029] The present invention provides a titanium dioxide aqueous dispersion comprising the following components in parts by weight: 60-75 parts nano titanium dioxide, 10-25 parts polyol, 1-5 parts polysaccharide polymer, and 10-20 parts water; wherein the polysaccharide polymer includes propylene glycol alginate.

[0030] In different embodiments, the weight parts of the nano-titanium dioxide may be, but are not limited to, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, and 75 parts.

[0031] In different embodiments, the weight parts of the polyol may be, but are not limited to, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, or 25 parts;

[0032] In different embodiments, the weight parts of the polysaccharide polymer may be, but are not limited to, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts;

[0033] In different embodiments, the weight parts of the water may be, but are not limited to, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, or 20 parts.

[0034] This invention incorporates polyols and polysaccharide polymers into an aqueous dispersion of titanium dioxide. The hydroxyl groups on the surface of the nano-titanium dioxide interact with the hydroxyl groups of the polysaccharide polymer through van der Waals forces, causing the nano-titanium dioxide to adsorb onto the surface of the polysaccharide polymer. This enhances the repulsive force between the nano-titanium dioxide particles and reduces their aggregation. Furthermore, in the presence of water, the polyol and polysaccharide polymer form supramolecular structures that interact through hydrogen bonds and van der Waals forces, significantly increasing the repulsive force between the nano-titanium dioxide particles and further improving the dispersibility of the nano-titanium dioxide. Consequently, this improves the stability of cosmetics containing the aqueous dispersion of nano-titanium dioxide, especially the stability, skin feel, and sun protection effect of water-in-oil sunscreens.

[0035] In some embodiments, the polysaccharide polymer further includes at least one of the following: Carrageenan extract, sodium carrageenan, gum arabic, arabar gum, and carboxymethyl chitosan.

[0036] In this invention, when the polysaccharide polymer also includes the above-mentioned components, it can further improve the dispersibility of the titanium dioxide aqueous dispersion and the stability and sun protection effect of the water-in-oil sunscreen product.

[0037] In some embodiments, the polysaccharide polymer is propylene glycol alginate and chondrus crispus extract, with a mass ratio of propylene glycol alginate to chondrus crispus extract of 7:1 to 1:3, for example, but not limited to 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3.

[0038] In this invention, when the polysaccharide polymers are propylene glycol alginate and Chondrus crispus extract, the dispersibility of the titanium dioxide aqueous dispersion and the stability and sun protection effect of the water-in-oil sunscreen product are better.

[0039] In some embodiments, the polyol is at least one selected from glycerol, ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, pentylene glycol, hexanediol, and methylpropanediol.

[0040] In some embodiments, the polyol is dipropylene glycol and methylpropylene glycol, and the mass ratio of dipropylene glycol to methylpropylene glycol is 1.5-4, for example, but not limited to 1.5, 2, 2.5, 3, 3.5, 4.

[0041] In this invention, when the polyols are dipropylene glycol and methyl propylene glycol, the dispersibility of the titanium dioxide aqueous dispersion and the stability and sun protection effect of the water-in-oil sunscreen product are better.

[0042] In some embodiments, the nano-titanium dioxide is modified with a surface treatment agent, which is at least one selected from silane coupling agent, hydrogenated polydimethylsiloxane, silicon dioxide, aluminum hydroxide, and amino acids.

[0043] The surface modifiers described above can be used to coat titanium dioxide, which can improve the dispersibility of nano-titanium dioxide in water and oil media, and enable titanium dioxide to be uniformly dispersed in water and oil media.

[0044] There are no particular restrictions on the shape of the titanium dioxide particles, and particles of any shape can be used, such as spherical particles, rod-shaped particles, needle-shaped particles, spindle-shaped particles, and plate-shaped particles. For particles with shapes other than spherical, the average primary particle size is defined by the average length of the shorter axis sides in the case of rod-shaped, needle-shaped, and spindle-shaped particles, while in the case of plate-shaped particles, the average primary particle size is defined by the average length of the diagonal on the surface.

[0045] The ratio of the major axis diameter to the minor axis diameter of a titanium dioxide particle is called the aspect ratio. The aspect ratio is preferably 3 or less, and more preferably 1 to 2. The aspect ratio of titanium dioxide particles is calculated as the average of the ratio of the major axis diameter to the minor axis diameter of 200 randomly selected particles under an electron microscope.

[0046] The crystal structure of titanium dioxide particles is not particularly limited, and for example, anatase, rutile, or brookite types can be used. From the perspective of suppressing photocatalytic activity, the rutile type is preferred. In addition to titanium dioxide (TiO2), titanium dioxide particles can also be compounds represented by metatitanate (TiO2·nH2O) and orthotitanate (Ti(OH)4).

[0047] Titanium dioxide particles can be prepared by various known methods. As a method for preparing the aforementioned titanium dioxide particles with a relatively small average primary particle size, for example, the following methods can be employed: a method in which an aqueous solution of titanium tetrachloride is hydrolyzed by neutralization with an alkali and the resulting hydrated titanium dioxide is calcined (this is also referred to as the "calcination method" in this application); and a method in which an aqueous solution of titanium tetrachloride is hydrolyzed by neutralization with an alkali, the resulting hydrated titanium dioxide is heat-treated with sodium hydroxide, and the resulting reaction product is heated and matured with acid (this is also referred to as the "wet method" in this application). Generally, spherical titanium dioxide particles can be obtained by the above calcination method, and spindle-shaped titanium dioxide particles can be obtained by the above wet method. Furthermore, rutile titanium dioxide particles can be obtained by both the calcination method and the wet method. Moreover, the titanium dioxide particles obtained by the calcination method have an aspect ratio of approximately 3 or less. Preferably, spherical particles with an aspect ratio of 1 to 2 can be obtained.

[0048] In spherical titanium dioxide particles obtained by calcination, the increased crystallinity due to calcination significantly suppresses photocatalytic activity. Therefore, the use of spherical titanium dioxide particles obtained by calcination is preferred in cosmetics.

[0049] The average particle size of nano-titanium dioxide is 10-40nm, for example, but not limited to 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, and 40nm, and its test method is GB / T 19077-2016.

[0050] In a second aspect, a method for preparing the titanium dioxide aqueous dispersion is provided, comprising the following steps: mixing polyol and polysaccharide polymer evenly, adding water and heating to 60-80℃ and stirring until transparent, then adding nano-titanium dioxide, homogenizing at a speed of 5000-8000 r / min for 3-5 min, stirring and cooling to room temperature to obtain the titanium dioxide aqueous dispersion.

[0051] In different embodiments, the homogenization speed can be, but is not limited to, 5000 r / min, 5500 r / min, 6000 r / min, 6500 r / min, 7000 r / min, 7500 r / min, or 8000 r / min.

[0052] In this invention, the titanium dioxide aqueous dispersion prepared by the above method has better dispersibility.

[0053] Thirdly, the application of the titanium dioxide dispersion in cosmetics is provided.

[0054] Fourthly, a cosmetic product is provided, comprising the titanium dioxide aqueous dispersion, wherein the titanium dioxide aqueous dispersion comprises 6-15% by mass in the cosmetic product, for example, but not limited to 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0055] Cosmetics prepared using the titanium dioxide aqueous dispersion of the present invention can be prepared by mixing the aqueous dispersion with optional cosmetic ingredients. Optional cosmetic ingredients may include components such as: oils, surfactants, humectants, higher alcohols, metal ion chelators, natural and synthetic polymers, water-soluble and oil-soluble polymers, UV shielding agents, various extracts, colorants including pigments and organic dyes, preservatives, antioxidants, dyes, thickeners, pH adjusters, fragrances, cooling agents, antiperspirants, fungicides, skin activators, and various powders. Mixtures of these components can be prepared in various forms, such as creams, pastes, sticks, and emulsions.

[0056] In some embodiments, the cosmetic is a sunscreen lotion, and the sunscreen lotion comprises the following components in weight percentage: 6-15% titanium dioxide aqueous dispersion, 5-15% organic sunscreen agent, 5-30% oil, 0.5-5% emulsifier, 0.1-5% skin conditioning agent, 0.1-20% moisturizer, 0.05-5% rheology modifier, 0.05-3% antioxidant, 0.1-0.6% preservative, 0.05-5% pH adjuster, 0.01-1% fragrance, and the balance being water.

[0057] The sunscreen lotion of this invention contains a titanium dioxide aqueous dispersion (an inorganic sunscreen agent) and an organic sunscreen agent. The two different types of sunscreen agents are used in combination, and the lotion contains a high dose of titanium dioxide aqueous dispersion, which reduces the skin irritation caused by the organic sunscreen agent. At the same time, it can effectively prevent ultraviolet rays from damaging the skin and improve the sun protection effect of the sunscreen lotion. In addition, the titanium dioxide aqueous dispersion has good dispersibility in the sunscreen lotion, which can effectively reduce the aggregation of titanium dioxide, so that the sunscreen lotion does not leave a white cast after application, has a refreshing feel, and has good breathability and sun protection effect.

[0058] In different embodiments, the weight percentage of the titanium dioxide aqueous dispersion may be, but is not limited to, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0059] In different embodiments, the weight percentage of the organic sunscreen agent may be, but is not limited to, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0060] In different embodiments, the weight percentage of the oil can be, but is not limited to, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 28%, or 30%.

[0061] In different embodiments, the emulsifier may be present in, but is not limited to, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% by weight.

[0062] In different embodiments, the weight percentage of the skin conditioning agent may be, but is not limited to, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0063] In different embodiments, the humectant may be, but is not limited to, 0.1%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, or 20% by weight;

[0064] In different embodiments, the rheology modifier may be present in, but is not limited to, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% by weight.

[0065] In different embodiments, the antioxidant may be present in, but is not limited to, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3% by weight.

[0066] In different embodiments, the preservative may be present in, but is not limited to, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, or 0.6% by weight.

[0067] In different embodiments, the weight percentage of the pH adjuster may be, but is not limited to, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0068] In different embodiments, the flavoring may be present in, but is not limited to, 0.01%, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, or 1% by weight.

[0069] In different embodiments, the organic sunscreen agent is one or more of the following: bis-ethylhexyloxyphenol methoxyphenyl triazine, butyl methoxydibenzoylmethane, hexyl diethylaminohydroxybenzoyl benzoate, diethylhexylbutamidotriazine ketone, disodium phenyl diimidazole tetrasulfonate, ethylhexyl methoxycinnamate, ethylhexyl salicylate, ethylhexyl triazine ketone, humosasulfate, isoamyl p-methoxycinnamate, methylene bis-benzotriazolyl tetramethylbutylphenol, octocrylene, and phenylbenzimidazole sulfonic acid.

[0070] In various embodiments, the oil is one or more of the following: ethylhexyl palmitate, dioctyl carbonate, hydrogenated polyisobutylene, butylene glycol cocoate, propylheptaethyl octanoate, isopropyl palmitate, isostearyl isostearate, C12-13 alcohol malate, caprylic / capric triglyceride, propylene glycol dicaprylate / dicaprylate, triglyceride tri(ethylhexanoate), hydrogenated polydecene, diisostearyl malate, isoamyl laurate, C12-15 alcohol benzoate, isohexadecane, cocoyl octanoate / capric ester, butyl octyl salicylate, lauroyl sarcosine isopropyl ester, and polydimethylsiloxane.

[0071] In different embodiments, the emulsifier is one or more of the following: potassium cetyl phosphate, cetyl phosphate, sodium stearoyl glutamate, glyceryl stearate / PEG-100 stearate, tris(lauryl ether-4) phosphate, stearyl ether-21, polyglycerol-2 dihydroxystearate, and polyglycerol-3 diisostearate.

[0072] In different embodiments, the skin conditioning agent is one or more of allantoin, nicotinamide, panthenol, β-glucan, inositol, asiaticoside, bisabolol, erythritol, and tocopheryl acetate.

[0073] In different embodiments, the humectant is one or more of glycerin, polyethylene glycol-8, betaine, trehalose, sodium polyglutamate, methyl glucetol polyether-10, methyl glucetol polyether-20, PPG-24-glycerol polyether-24, and PEG / PPG-17 / 6 copolymer.

[0074] In various embodiments, the rheology modifier is one or more of the following: ammonium acryloyldimethyl taurate / VP copolymer, acrylate copolymer, carbomer, sodium carbomer, acrylate / C10-30 alkanol acrylate crosspolymer, acrylate / behenol polyether-25 methacrylate copolymer, acrylate / palm oil alcohol polyether-25 methacrylate copolymer, PEG-240 / HDI copolymer bis-decyltetradecyl alcohol polyether-20 ether, acrylate / vinyl isodecanoate crosspolymer, ammonium acryloyldimethyl taurate / behenol polyether-25 methacrylate crosspolymer, hydroxyethyl acrylate / sodium acryloyldimethyl taurate copolymer, sodium polyacrylate, hydroxyethyl cellulose, and polyacrylate crosspolymer-6.

[0075] In different embodiments, the antioxidant is one or more of p-hydroxyacetophenone, tocopheryl acetate, butylated hydroxytoluene, pentaerythritol tetra(bis-tert-butylhydroxyhydrocinnamic acid) ester, and tert-butylhydroquinone.

[0076] In different embodiments, the preservative is one or more of methylparaben, phenoxyethanol, chlorphenesin, propylparaben, DMDM ​​hydantoin, and sodium benzoate.

[0077] In different embodiments, the pH adjuster is one or more of triethanolamine, aminomethylpropanol, sodium hydroxide, arginine, sodium citrate, and tromethamine.

[0078] The cosmetics of this invention can be prepared by any suitable method known in the art. For example, commonly used equipment in the cosmetics field, such as dissolving tanks, emulsifying pots, dispersers, and transfer pumps, can be used to prepare the product according to known processes. For example, water-soluble substances can be first added to an aqueous phase dissolving vessel, and oil-soluble substances (e.g., sunscreens, oils) can be added to an oil phase dissolving vessel. The temperatures of both vessels are heated to approximately 80°C. For raw materials that are prone to clumping, they can be pre-dispersed using a disperser. If the product contains powdery substances (e.g., zinc oxide, titanium dioxide), it can be dispersed with a suitable solvent and dispersant and homogenized for 5-10 minutes. Then, the oil phase is added, and homogenization is performed again for 5-10 minutes. After homogenization, the oil phase and aqueous phase are transferred to an emulsifying pot for homogenization and emulsification for approximately 5-15 minutes. After emulsification, the temperature of the material is lowered to room temperature. Optionally, fragrances, preservatives, etc., are added, and the pH of the product is adjusted as needed. After the relevant test indicators are qualified, the product can be filled and discharged.

[0079] The above preparation processes are merely illustrative examples. Those skilled in the art can add, subtract, or adjust them according to the dosage form requirements to prepare various dosage forms such as sprays, emulsions, gels / creams, creams, cushions / foundations, etc.

[0080] To further illustrate the present invention, the titanium dioxide aqueous dispersion, its preparation method, and its application provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0081] Examples and Comparative Examples

[0082] The present invention provides a titanium dioxide aqueous dispersion, the components and weight parts of which are shown in Table 1 and Table 2.

[0083] The preparation methods of the titanium dioxide aqueous dispersions in the examples and comparative examples are as follows:

[0084] Weigh each component according to the weight parts in Tables 1 and 2. Mix the polyol and polysaccharide polymer evenly, add water, heat to 70°C and stir until transparent. Then add nano-titanium dioxide with an average particle size of 25nm, homogenize at 6000r / min for 3min, and homogenize a total of 3 times. Stir and cool to room temperature to obtain a titanium dioxide aqueous dispersion.

[0085] Table 1

[0086]

[0087] Table 2

[0088]

[0089] Application Example 1-16, Comparison of Application Example 1-6 and Blank Application Example

[0090] This invention provides an oil-in-water sunscreen emulsion in application examples, comparative application examples, and a blank application example. The components (mass percentage) of the oil-in-water sunscreen emulsion are shown in Table 3. Specifically, the titanium dioxide aqueous dispersions used in application examples 1-12 are the titanium dioxide aqueous dispersions prepared in examples 1-12, and the titanium dioxide aqueous dispersions used in comparative application examples 1-6 are the titanium dioxide aqueous dispersions prepared in comparative examples 1-6. The titanium dioxide aqueous dispersions used in application examples 15-16 are the titanium dioxide aqueous dispersions prepared in example 1.

[0091] The preparation methods of the water-in-oil sunscreen emulsions used in the application examples, comparative application examples, and blank application examples are as follows:

[0092] Preparation of the aqueous phase: Water, skin conditioning agent, moisturizer, rheology modifier, and preservative are mixed evenly to obtain the aqueous phase;

[0093] Preparation of the oil phase: Mix the oil and emulsifier evenly, stir and heat to 80-90℃ to obtain the oil phase;

[0094] Preparation of emulsion: The oil phase and the aqueous phase are heated to 80-90℃ respectively, and then the oil phase is added to the aqueous phase. The emulsion is homogenized at 5000 rpm for 3 min to obtain the emulsion.

[0095] Preparation of oil-in-water sunscreen emulsion: The emulsion is cooled to room temperature, and then titanium dioxide aqueous dispersion and the remaining components are added and stirred evenly to obtain oil-in-water sunscreen emulsion.

[0096] Table 3

[0097]

[0098]

[0099] Example of effect 1

[0100] This effect example tests the appearance, dispersibility, pH, and viscosity of the titanium dioxide aqueous dispersions obtained in the examples and comparative examples.

[0101] The specific steps are as follows:

[0102] (1) Appearance: Visual inspection;

[0103] (2) Dispersibility: The titanium dioxide aqueous dispersions obtained in the examples and comparative examples were added to water and oil respectively, stirred for 1 min, and the dispersion of the titanium dioxide aqueous dispersions was visually observed.

[0104] (3) pH value: The pH value was tested using the dilution method in accordance with the Cosmetic Safety Technical Specifications (2015 edition).

[0105] (4) Viscosity: Tested at room temperature using (IKA ROTAVISC ME-VI, 8#, 15rpm).

[0106] (5) Appearance stability: The water-in-oil sunscreen was placed at 25℃ for 90 days and its appearance was visually observed.

[0107] Test results are as follows Figure 1-4 As shown in Table 4.

[0108] Table 4

[0109]

[0110]

[0111] like Figure 1-2 As shown, visual observation of the titanium dioxide aqueous dispersions of Examples 1-14 and Comparative Examples 1-6 reveals that they are all white and uniform dispersions; and they are easily dispersed in water but not easily dispersed in oil.

[0112] As can be seen from the experimental data in Table 4, the pH value of the titanium dioxide aqueous dispersion of the present invention is 5.5-6, and the viscosity is 500-1850 mPa·s.

[0113] Example 2

[0114] This test example examines the stability of the water-in-oil sunscreen obtained from the application example, the control application example, and the blank application example.

[0115] The specific steps are as follows:

[0116] (1) Instability index (room temperature stability): At 25℃, using a dispersion analyzer The 651 test quantifies the clarity (2) by dividing the clarity at a given separation time; the clarity quantifies the increase in transmittance (decreased particle concentration) due to phase separation caused by sedimentation or emulsification; where the instability index is a value between 0 and 1. “0” indicates that the particle concentration has not changed (very stable), and “1” indicates that the dispersion has separated (very unstable).

[0117] (2) Particle size: Tested using an optical microscope.

[0118] The test results are shown in Table 5.

[0119] Table 5

[0120]

[0121] As can be seen from the experimental data in Table 5, the instability index of the sunscreen lotion of the present invention is ≤0.17, the average particle size is ≤35μm, the average particle size after being placed at 45℃ for 24 hours is ≤35μm, and the average particle size after being placed at 45℃ for 90 days is ≤45μm, indicating that the sunscreen lotion of the present invention has high stability.

[0122] Comparing Application Example 1 and Application Examples 4-9, it can be seen that when the polysaccharide polymers are propylene glycol alginate and *Chlorella vulgaris* extract, the resulting sunscreen lotion has an instability index ≤0.102, an average particle size ≤22.5 μm, an average particle size ≤22.5 μm after being placed at 45°C for 24 hours, and an average particle size ≤31.5 μm after being placed at 45°C for 90 days. This indicates that when the polysaccharide polymers are propylene glycol alginate and *Chlorella vulgaris* extract, the resulting sunscreen lotion has better stability. High; when the mass ratio of propylene glycol alginate to *Chlorella vulgaris* extract is 7:1-1:3, the resulting sunscreen has an instability index ≤0.092, an average particle size ≤21.5μm, an average particle size ≤21.5μm after being placed at 45℃ for 24 hours, and an average particle size ≤31.5μm after being placed at 45℃ for 90 days. This indicates that when the mass ratio of propylene glycol alginate to *Chlorella vulgaris* extract is 7:1-1:3, the resulting sunscreen has higher stability.

[0123] Comparing Application Example 1 and Application Examples 10-14, when the polyols are dipropylene glycol and methylpropylene glycol, the resulting sunscreen has an instability index ≤0.135, an average particle size ≤29μm, an average particle size ≤29μm after being placed at 45℃ for 24 hours, and an average particle size ≤40μm after being placed at 45℃ for 90 days. This indicates that the sunscreen has higher stability when the polyols are dipropylene glycol and methylpropylene glycol. When the mass ratio of dipropylene glycol to methylpropylene glycol is 1.5-4, the resulting sunscreen has an instability index ≤0.12, an average particle size ≤26μm, an average particle size ≤26μm after being placed at 45℃ for 24 hours, and an average particle size ≤36μm after being placed at 45℃ for 90 days. This indicates that the sunscreen has higher stability when the mass ratio of dipropylene glycol to methylpropylene glycol is 1.5-4.

[0124] Comparing Application Example 1 and Comparative Application Examples 1-6, it can be seen that the absence of at least one of the polysaccharide polymer and polyol, the use of a monohydric alcohol to replace the polyol, or the excessive addition of polysaccharide polymer will all lead to a significant increase in the instability index and average particle size of the sunscreen.

[0125] Example 3

[0126] This test evaluated the skin feel and sun protection effect of the water-in-oil sunscreen obtained from the application example, the control application example, and the blank application example.

[0127] The specific steps are as follows:

[0128] The testing method for the skin feel score is as follows: referring to T / GDCA 003—2020 T / GDCA General Rules for Sensory Evaluation of Cosmetics, 30 volunteers were recruited and evaluated from five dimensions: ease of application (0-5 points corresponding to difficult to apply to easy to apply), water feel (0-5 points corresponding to weak water feel to strong water feel), skin smoothness (0-5 points corresponding to rough to smooth), skin stickiness (0-5 points corresponding to sticky to non-sticky), and overall absorption speed (0-5 points corresponding to slow to fast). The comprehensive score is the average of the five scores, and the higher the score, the better the skin feel.

[0129] The test method for immediate sun protection effect is as follows: refer to SN / T 5150-2019, the in vitro test method for UVA photoprotection effect of sunscreen cosmetics, and test the prepared sunscreen lotion on a UV-2000S device.

[0130] The formula for calculating SPF is:

[0131]

[0132] In Equation 1, E(λ) is the erythema effect coefficient.

[0133] I(λ) — Radiation intensity of UV light source;

[0134] A0—The average monochromatic absorbance of each sample before UV irradiation;

[0135] d(λ) — Wavelength step size (nm).

[0136] The formula for calculating PA is:

[0137]

[0138] In Equation 2, P(λ) is the PPD spectral index.

[0139] I(λ) — Spectral irradiance of UVA light source;

[0140] A0 – Monochromatic light absorption of the test slide before exposure to UV;

[0141] C—Adjustment coefficient;

[0142] dλ — Measurement wave step length (nm).

[0143] The test method for long-lasting sun protection effect is as follows: place the sunscreen lotions of the application example and the control application example at a temperature of 45°C for 90 days, and then test the SPF and PA values ​​of the sunscreen lotions according to the test method for sun protection effect.

[0144] The test results are shown in Table 6.

[0145] Table 6

[0146]

[0147]

[0148] As can be seen from the experimental data in Table 6, the SPA value of the sunscreen lotion of the present invention is ≥39.7 and the PA value is ≥8.4. After being placed at a temperature of 45℃ for 90 days, the SPA value is ≥33.4 and the PA value is ≥6.2, indicating that the sunscreen lotion of the present invention has good immediate and long-lasting sun protection effects.

[0149] Comparing Application Example 1 and Application Examples 4-9, it can be seen that when the polysaccharide polymer is propylene glycol alginate and *Caulis Chlamydosus* extract, the resulting sunscreen lotion has a SPA value ≥ 53 and a PA value ≥ 12.8. After being placed at 45℃ for 90 days, the SPA value is ≥ 44 and the PA value is ≥ 9. This indicates that when the polysaccharide polymer is propylene glycol alginate and *Caulis Chlamydosus* extract, the resulting sunscreen lotion has better and longer-lasting sun protection effects. When the mass ratio of propylene glycol alginate to *Caulis Chlamydosus* extract is 7:1-1:3, the resulting sunscreen lotion has a SPA value ≥ 53.5 and a PA value ≥ 13. After being placed at 45℃ for 90 days, the SPA value is ≥ 45 and the PA value is ≥ 9.5. This indicates that when the polysaccharide polymer is propylene glycol alginate and *Caulis Chlamydosus* extract, the resulting sunscreen lotion has better and longer-lasting sun protection effects.

[0150] Comparing Application Example 1 and Application Examples 10-14, when the polyols are dipropylene glycol and methylpropylene glycol, the resulting sunscreen lotion has a SPA value ≥ 51 and a PA value ≥ 12.5. After being placed at 45°C for 90 days, the SPA value is ≥ 42 and the PA value is ≥ 9. This indicates that when the polyols are dipropylene glycol and methylpropylene glycol, the resulting sunscreen lotion has higher immediate and long-lasting sun protection effects. When the mass ratio of dipropylene glycol to methylpropylene glycol is 1.5-4, the resulting sunscreen lotion has a SPA value ≥ 55 and a PA value ≥ 13.5. After being placed at 45°C for 90 days, the SPA value is ≥ 47 and the PA value is ≥ 10. This indicates that when the mass ratio of dipropylene glycol to methylpropylene glycol is 1.5-4, the resulting sunscreen lotion has higher immediate and long-lasting sun protection effects.

[0151] Comparing Application Example 1 and Comparative Application Examples 1-6, it can be seen that the absence of at least one of the polysaccharide polymer and polyol, the use of a monohydric alcohol to replace the polyol, or the excessive addition of polysaccharide polymer will all lead to a significant decrease in the immediate and long-lasting sun protection effects of the sunscreen.

[0152] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this disclosure and not to limit the scope of protection of this disclosure. Although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this disclosure without departing from the substance and scope of the technical solutions of this disclosure.

Claims

1. A titanium dioxide aqueous dispersion, characterized in that, It is composed of the following components in parts by weight: 60-75 parts nano titanium dioxide, 10-25 parts polyol, 1-5 parts polysaccharide polymer and 10-20 parts water; wherein the average particle size of the nano titanium dioxide is 10-40 nm. The polysaccharide polymer is propylene glycol alginate and Chondrus crispus extract, with a mass ratio of propylene glycol alginate to Chondrus crispus extract of 7:1-1:

3. Alternatively, the polysaccharide polymer is propylene glycol alginate and erythrina gum, with a mass ratio of propylene glycol alginate to erythrina gum of 1:

1. Alternatively, the polysaccharide polymer is propylene glycol alginate and carboxymethyl chitosan, with a mass ratio of propylene glycol alginate to carboxymethyl chitosan of 1:

1.

2. The titanium dioxide aqueous dispersion as described in claim 1, characterized in that, The polyol is at least one of glycerol, ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, pentylene glycol, hexanediol, and methylpropanediol.

3. The titanium dioxide aqueous dispersion as described in claim 2, characterized in that, The polyol is dipropylene glycol and methyl propylene glycol, with a mass ratio of 1.5-4.

4. The titanium dioxide aqueous dispersion as described in claim 1, characterized in that, The nano-titanium dioxide is modified with a surface treatment agent, which is at least one of silane coupling agent, hydrogenated polydimethylsiloxane, silicon dioxide, aluminum hydroxide, and amino acids.

5. The method for preparing the titanium dioxide aqueous dispersion according to any one of claims 1-4, characterized in that, The process includes the following steps: after mixing polyol and polysaccharide polymer evenly, water is added and the temperature is raised to 60-80℃ and stirred until transparent. Then, nano-titanium dioxide is added and homogenized at a speed of 5000-8000 r / min for 3-5 min. After stirring and cooling to room temperature, a titanium dioxide aqueous dispersion is obtained.

6. The use of the titanium dioxide dispersion as described in any one of claims 1-4 in the preparation of cosmetics.

7. A cosmetic product, characterized in that, Includes the titanium dioxide aqueous dispersion as described in any one of claims 1-4, wherein the titanium dioxide aqueous dispersion has a mass percentage content of 6-15% in the cosmetic.

8. The cosmetic product as described in claim 7, characterized in that, The cosmetic is a sunscreen lotion, and the sunscreen lotion comprises the following components in weight percentage: 6-15% titanium dioxide aqueous dispersion, 5-15% organic sunscreen agent, 5-30% oil, 0.5-5% emulsifier, 0.1-5% skin conditioning agent, 0.1-20% moisturizer, 0.05-5% rheology modifier, 0.05-3% antioxidant, 0.1-0.6% preservative, 0.05-5% pH adjuster, 0.01-1% fragrance, and the balance being water.

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