Flower-like cerium oxide as well as preparation method and application thereof

Abstract

The invention belongs to the field of powder material preparation, and discloses flower-like cerium oxide as well as a preparation method and application thereof. According to the invention, a water-soluble high-molecular compound is used as an organic framework template agent to regulate and synthesize flower-like cerium oxide, a conventional industrial common liquid phase precipitation method is adopted, a reaction unit is constructed by an aqueous solution system of polyvinylpyrrolidone (PVP) with different polymerization degrees, soluble cerium salt is used as a raw material, a carbonate-containing precipitant is added, and the flower-like cerium oxide is prepared. The flower-like cerium oxide particles used in cosmetics are prepared through aging, filtering, drying and roasting, the specific surface area of flower-like cerium oxide reaches 103.702-110 m < 2 > / g, the ultraviolet absorption area is mainly 200-350 nm, and compared with a sample without PVP, the flower-like cerium oxide particles have the advantages that the absorption strength and range are remarkably increased, the friction coefficient is smaller than or equal to 0.500, and the skin feeling is better.

Description

Technical Field

[0001] This invention relates to the field of powder material preparation technology, and more specifically to a method for preparing flower-shaped cerium oxide for use in cosmetics to enhance ultraviolet shielding capabilities. Background Technology

[0002] Lanthanide rare earths account for 79% of the rare earth resources in Bayan Obo, Baotou, with Ce resources accounting for as much as 50%. Expanding the application of lanthanum and cerium products, especially increasing the added value of Ce products and expanding the application of Ce resources, is currently a key research project of Northern Rare Earth Group.

[0003] Intrinsic properties of cerium: Ce 4+ (240nm); Ce 3+ (314nm), CeO2 particles through their Ce 3+ / Ce 4+ Redox reactions play a protective role for cells exposed to ultraviolet radiation, buffering oxidation, maintaining cell viability and proliferation, and reducing DNA damage. This has led to significant interest in CeO2 for its application in shielding ultraviolet radiation. The strength of CeO2's UV resistance is related to its morphology and particle size.

[0004] Previously, the laboratory successfully prepared uniformly morphologically uniform flower-shaped cerium oxide crystals using PAH as a template agent. This material can replace the UV-resistant material jointly developed by a Japanese cosmetics company and a Japanese inorganic chemical industry company. According to the company, the flower-shaped cerium oxide exhibits excellent application effects. However, PAH as a template agent is relatively expensive. To find a relatively low-cost preparation method, the laboratory conducted extensive research and discovered that polyvinylpyrrolidone (PVP) can replace PAH. Therefore, using PVP with different degrees of polymerization, cerium-based precursors with flower-shaped morphologies were generated, and calcination yielded oxide powders with the inherited precursor morphology. PVP, as a nonionic polymeric surfactant, is currently widely used in the synthesis of organic-inorganic composite materials. By adding PVP to regulate the grain growth process, samples can obtain various morphologies such as spherical, plate-like, and cubic shapes, thereby preparing advanced materials with specific structures and functions. Chinese patent CN115058199A discloses a highly dispersed spherical cerium oxide polishing slurry for use in the ultra-precision machining of semiconductors. It utilizes PVP to control the synthesis of spherical cerium oxide, giving it a highly dispersed, highly fluid, and low-roughness surface.

[0005] Therefore, developing a low-cost preparation process for flower-shaped cerium oxide for cosmetics is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Currently, there is a great demand for ultraviolet shielding materials. In view of this, the present invention provides a flower-shaped cerium oxide, its preparation method and application. Based on the fact that CeO2 particles are non-toxic to the human body, have high user comfort, high gloss and strong anti-ultraviolet ability, polyvinylpyrrolidone is selected to prepare flower-shaped cerium oxide crystals with uniform morphology, which reduces the cost of preliminary experiments.

[0007] One objective of this invention is to provide a flower-like cerium oxide with a specific surface area of ​​103.702-110 m². 2 / g, the absorption range of ultraviolet light is mainly in the range of 200-350nm. Compared with the sample without added PVP, the absorption range is significantly increased, the coefficient of friction is ≤0.500, and the skin feel is better.

[0008] Flower-shaped cerium oxide was synthesized by using water-soluble polymers as templates. A liquid-phase precipitation method was adopted, using polyvinylpyrrolidone (PVP) with different degrees of polymerization as templates and soluble cerium salts as raw materials. A precipitant containing carbonate was added, and the ketone groups in PVP were used to regulate the crystal nucleation and growth process to prepare cerium-based precursors with flower-like morphology. The precursors were then calcined to obtain oxide powders with the genetic precursor morphology.

[0009] The second objective of this invention is to provide a method for preparing flower-like cerium oxide, the specific steps of which are as follows: (1) Preparation of a mixed solution of PVP and cerium salt: Weigh the cerium salt, dissolve it in water, prepare a cerium salt solution with a concentration of 1.55 mol / L, and adjust the pH value to 2-5; Weigh polyvinylpyrrolidone, stir and add it to the cerium salt solution until it is mixed evenly, and set aside. (2) Preparation of precipitant solution: Weigh the precipitant, add water to dissolve it, stir and mix evenly, and set aside; (3) Preparation of flower-shaped cerium carbonate particles: The precipitant solution is added at a constant rate to the mixed solution of cerium salt and PVP. After the addition is completed, the mixture is stirred, aged, filtered, washed and dried to obtain flower-shaped cerium carbonate particles. (4) Preparation of flower-shaped cerium oxide: Transfer the flower-shaped cerium carbonate particles to a muffle furnace, calcine them, and then cool them to room temperature with the furnace to obtain flower-shaped cerium oxide particles.

[0010] Preferably, in step (1), the cerium salt is water-soluble Ce. 3+ Salt compounds; more preferably, the cerium salt is cerium nitrate, cerium chloride, cerium acetate, or cerium sulfate, etc.

[0011] Preferably, the polyvinylpyrrolidone is K-15, K-30, K-60 or K-90, with average molecular weights of 10,000, 58,000, 220,000 and 1,300,000, respectively.

[0012] Preferably, in step (1), in the mixed solution of cerium salt and PVP, Ce 3+ The concentration of the active ingredient is 0.01–0.11 mol / L, and the concentration of polyvinylpyrrolidone is 0.1–2.5 g / L.

[0013] Preferably, in step (2), the precipitant is a soluble carbonate containing carbonate ions; the concentration of the precipitant is 0.01 to 0.10 mol / L.

[0014] More preferably, the soluble carbonate is ammonium carbonate, ammonium bicarbonate, sodium carbonate, or sodium bicarbonate, etc.

[0015] Preferably, in step (3), the mass ratio of the precipitant to the cerium salt oxide is 1-2.

[0016] Preferably, in step (3), the feeding time is 0 to 2 hours, and after the feeding is completed, stirring continues for 0.5 hours, followed by aging for 0 to 48 hours.

[0017] Preferably, in step (3), the washing and drying operations are as follows: the filter cake after filtration is washed 3 times with deionized water, washed 2 times with alcohol, and dried at 60°C for 2 hours to obtain uniformly dispersed flower-shaped cerium carbonate particles.

[0018] Preferably, in step (4), the calcination is carried out at 400-1000℃ for 4h to 12h.

[0019] More preferably, the roasting is at 400°C, 500°C, or 1000°C.

[0020] The third objective of this invention is to apply the flower-shaped cerium oxide to cosmetics.

[0021] This invention provides a method for preparing flower-shaped cerium oxide with improved ultraviolet shielding capability, utilizing the ketone oxygen group on the side chain of polyvinylpyrrolidone and Ce. 3+ The adsorption of ions provides induced nucleation sites for cerium carbonate crystals. With the addition of carbonate ions, cerium carbonate crystals react with PVP and Ce. 3+ By combining positional nucleation growth, the different adsorption energies of PVP on each crystal facet of cerium carbonate crystal control the growth orientation and morphology. As the cerium carbonate crystal gradually grows, the carbon chains of the PVP molecules continuously twist and bend, causing the cerium carbonate monomers to gradually approach each other and eventually accumulate into a flower-like structure. After calcination, flower-shaped cerium oxide particles for use in cosmetics are prepared.

[0022] As can be seen from the above technical solution, compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) This invention uses water-soluble polymers as templates to regulate the synthesis of flower-shaped cerium oxide. Flower-shaped cerium oxide for use in cosmetics is prepared by liquid-phase precipitation. The entire reaction process is carried out at room temperature. The reaction conditions are mild, the preparation method is simple, and it is easy to control.

[0023] (2) This invention is the first to utilize polyvinylpyrrolidone (PVP) with different degrees of polymerization as template agents to regulate the synthesis of flower-shaped cerium oxide for use in cosmetics. The flower-shaped cerium oxide obtained by this invention is non-toxic to the human body, has high user comfort and high gloss. The flower-shaped morphology of the prepared cerium oxide crystals is affected by the regulation of pyrrole groups, which improves the ability to effectively absorb ultraviolet light. It can be used as a sunscreen agent and added to cosmetics as an ultraviolet absorber. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a SEM image of the irregularly shaped cerium oxide particles prepared in Comparative Example 1 of this invention. Figure 2 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 1 of the present invention; Figure 3 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 2 of the present invention; Figure 4 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 3 of the present invention; Figure 5 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 4 of the present invention; Figure 6 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 5 of the present invention.

[0026] Figure 7 This is a SEM image of the flower-shaped cerium oxide particles prepared in Example 6 of the present invention.

[0027] Figure 8 The N2 adsorption-desorption isotherms are shown for the flower-shaped cerium oxide and the cerium oxide particles without PVP prepared in Example 1 of this invention.

[0028] Figure 9 The images show the UV absorption spectra of flower-shaped cerium oxide and cerium oxide particles without PVP prepared in Example 1 of this invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the specific embodiments of this invention, (NH4)2CO3 and NH4HCO3 were produced by Tianjin Reagent Factory No. 3, polyvinylpyrrolidone was produced by Shanghai Maclean Biochemical Technology Co., Ltd., and ethanol was an analytical grade product.

[0031] Comparative Example 1 Cerium oxide particles were synthesized without the addition of polyvinylpyrrolidone, as a control experiment: (1) Prepare a 1.55 mol / L cerium nitrate solution, adjust the pH to 5, take 7.5 ml of this solution into a 1000 ml beaker, add water to 233 ml, so that [Ce] 3+ The concentration is 0.05 mol / L. (2) Weigh 3g of ammonium bicarbonate as precipitant, add 625mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the cerium salt solution at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. The solution was aged for 4 hours, filtered, dried, and calcined at 400℃ for 4 hours to obtain irregularly shaped cerium oxide particles (e.g., Figure 1 ).

[0032] Example 1 (1) Prepare a 1.55 mol / L cerium nitrate solution, adjust the pH to 5, take 7.5 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.466 g of polyvinylpyrrolidone (K-30), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[PVP]] is 0.05 mol / L, and the concentration of [PVP] is 2 g / L. (2) Weigh 3g of ammonium bicarbonate as precipitant, add 625mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. The mixture was aged for 4 hours, filtered, dried, and calcined at 400℃ for 4 hours to obtain flower-shaped cerium oxide particles (e.g., Figure 2 ).

[0033] The friction coefficient of the flower-shaped cerium oxide particles prepared in Example 1 was tested. The test items were friction coefficients (static and dynamic). The test standard was GB10006-1988. The test conditions were: sample size 63×63mm, test speed 100mm / min, friction mode: leather sample against leather sample, leather sample against leather sample, sample evenly sprinkled in the middle, and the total mass of the slider and leather sample was 204g. The test results are shown in Table 1.

[0034] Table 1

[0035] Example 2 (1) Prepare a 1.55 mol / L cerium nitrate solution, adjust the pH to 5, take 7.5 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.1398 g of polyvinylpyrrolidone (K-60), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[P]] is 0.05 mol / L, and the concentration of [PVP] is 0.6 g / L; (2) Weigh 3g of ammonium carbonate precipitant, add 680mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. The mixture was aged for 4 hours, filtered, dried, and calcined at 400℃ for 4 hours to obtain flower-shaped cerium oxide particles (e.g., Figure 3 ).

[0036] Example 3 (1) Prepare a 1.55 mol / L cerium nitrate solution, adjust the pH to 5, take 7.5 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.0233 g of polyvinylpyrrolidone (K-90), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[P]] is 0.05 mol / L, and the concentration of [PVP] is 0.1 g / L. (2) Weigh 3g of ammonium carbonate precipitant, add 680mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. The mixture was aged for 4 hours, filtered, dried, and calcined at 500℃ for 4 hours to obtain flower-shaped cerium oxide particles (e.g. Figure 4 ).

[0037] Example 4 (1) Prepare a 1.25 mol / L cerium chloride solution, adjust the pH to 5, take 9.3 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.5359 g of polyvinylpyrrolidone (K-30), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[[[[[[[[]]] is 0.075 mol / L], and the concentration of [[[PVP]] is 2.3 g / L; (2) Weigh 3g of ammonium bicarbonate as precipitant, add 625mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. After aging for 4 hours, the solution was filtered, dried, and calcined at 400℃ for 6 hours to obtain flower-shaped cerium oxide particles (e.g., Figure 5 ).

[0038] Example 5 (1) Prepare a 1.25 mol / L cerium chloride solution, adjust the pH to 5, take 9.3 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.233 g of polyvinylpyrrolidone (K-60), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[PVP]] is 0.075 mol / L, and the concentration of [PVP] is 1 g / L. (2) Weigh 3g of ammonium carbonate precipitant, add 680mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours, and the mixture was aged for 4 hours. After filtration, drying, and calcination at 500℃ for 6 hours, flower-shaped cerium oxide particles (such as...) were obtained. Figure 6 ).

[0039] Example 6 (1) Prepare a 1.25 mol / L cerium chloride solution, adjust the pH to 5, take 9.3 ml of this solution into a 1000 ml beaker, and add water to 233 ml; weigh 0.0466 g of polyvinylpyrrolidone (K-90), add it to the cerium salt solution to dissolve, and stir until homogeneous, so that [Ce 3+ The concentration of [[P]] was 0.075 mol / L, and the concentration of [PVP] was 0.2 g / L. (2) Weigh 3g of ammonium carbonate precipitant, add 625mL of water to dissolve, and stir to mix evenly; (3) The precipitant solution was added to the mixed solution of cerium nitrate and polyvinylpyrrolidone at a certain flow rate using a peristaltic pump. The addition time was 1 hour. After the addition was completed, stirring was continued for 0.5 hours. The mixture was aged for 4 hours, filtered, dried, and calcined at 1000℃ for 6 hours to obtain flower-shaped cerium oxide particles (e.g. Figure 7 ).

[0040] This invention utilizes polyvinylpyrrolidone (PVP) with different degrees of polymerization as template agents and employs a liquid-phase precipitation method to prepare cerium-based precursors with flower-like morphologies. Calcination then yields oxide powders with inherited precursor morphologies. The particle specific surface area reaches 107.702-110 m². 2 / g, the absorption region for ultraviolet light is mainly in the 200-350nm range. Compared with the sample without PVP, the absorption intensity and range are significantly increased, the coefficient of friction is ≤0.500, and the skin feel is better. Specifically, the preferential reaction of the ketone group in polyvinylpyrrolidone with Ce... 3+ Complexation and the formation of nucleation sites allow for the control of nucleation and crystal growth through electron adsorption and steric hindrance. This enables the control and regulation of the morphology, size, and structure of cerium carbonate crystals, ultimately controlling the morphology and size of cerium oxide. Furthermore, the flower-like cerium oxide obtained in this invention is non-toxic to humans, offers high user comfort and gloss, and the cerium oxide crystals prepared are enhanced by pyrrole, resulting in improved ultraviolet light absorption. Therefore, it can be used as a sunscreen agent and added to cosmetics as an ultraviolet absorber.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flower-shaped cerium oxide, characterized in that, The specific surface area of ​​the flower-like cerium oxide is 103.702-110 m². 2 / g, the absorption region for ultraviolet light is 200-350nm, and the coefficient of friction is ≤0.

500.

2. The method for preparing flower-like cerium oxide as described in claim 1, characterized in that, The specific steps are as follows: (1) Preparation of a mixed solution of PVP and cerium salt: Weigh the cerium salt, dissolve it in water, prepare a cerium salt solution, stir polyvinylpyrrolidone into the cerium salt solution until it is mixed evenly, and set aside; (2) Preparation of precipitant solution: Weigh the precipitant, add water to dissolve it, stir and mix evenly, and set aside; (3) Preparation of flower-shaped cerium carbonate particles: The precipitant solution is added at a constant rate to the mixed solution of cerium salt and PVP. After the addition is completed, the mixture is stirred, aged, filtered, washed and dried to obtain flower-shaped cerium carbonate particles. (4) Preparation of flower-shaped cerium oxide: After calcining the flower-shaped cerium carbonate particles, cool them to room temperature in the furnace to obtain flower-shaped cerium oxide particles.

3. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (1), the cerium salt is water-soluble Ce. 3+ Salt compounds; The polyvinylpyrrolidone is K-15, K-30, K-60 or K-90, with average molecular weights of 10,000, 58,000, 220,000 and 1,300,000, respectively.

4. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (1), the concentration of the cerium salt solution is 1.55 mol / L, and the pH value is 2 to 5; In the mixed solution of cerium salt and PVP, Ce 3+ The concentration of the active ingredient is 0.01–0.11 mol / L, and the concentration of polyvinylpyrrolidone is 0.1–2.5 g / L.

5. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (2), the precipitant is a soluble carbonate containing carbonate ions; the concentration of the precipitant is 0.01 to 0.10 mol / L.

6. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (3), the mass ratio of the precipitant to the oxide of the cerium salt is 1 to 2.

7. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (3), the feeding time is 0-2h, and after the feeding is completed, stirring continues for 0.5h, and aging lasts for 0-48h.

8. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (3), the washing and drying operations are as follows: the filter cake after vacuum filtration is washed 3 times with deionized water, washed 2 times with alcohol, and dried at 60°C for 2 hours to obtain uniformly dispersed flower-shaped cerium carbonate particles.

9. The method for preparing flower-like cerium oxide as described in claim 2, characterized in that, In step (4), the roasting is carried out at 400-1000℃ for 4h to 12h.

10. The application of the flower-shaped cerium oxide as described in claim 1 or the flower-shaped cerium oxide obtained by any of the methods described in claims 2-9 in cosmetics.

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