A structure of double-layer coated zinc oxide particles and its preparation method, an oil-phase pre-emulsified suspension composition, and pet- and baby-friendly non-toxic sunscreen products.

Abstract

This invention provides a double-layer coated zinc oxide particle structure applicable to zinc oxide particles with a particle size greater than 100 nanometers. The structure comprises a first layer coating the zinc oxide particles, the first layer being selected from polyhydroxystearic acid; and a second layer coating the outer side of the first layer, the second layer being selected from natural wax materials. This structure can inhibit zinc ion release, improve emulsion compatibility and UVA shielding effect, and possesses toxicological safety thresholds. It can be further formulated into oil-phase pre-emulsified suspension compositions and pet- and baby-friendly non-toxic sunscreen products.

Claims

1. A structure for double-layer coated zinc oxide particles, applied to zinc oxide particles, characterized in that the double-layer coated zinc oxide particle structure comprises: A first layer structure, which encapsulates the zinc oxide particles, is selected from polyhydroxystearic acid (PHSA); and a second layer structure, which is selected from natural waxes and esters, covers the outside of the first layer structure.

2. The structure of double-layered coated zinc oxide particles as described in claim 1, wherein, The natural waxes and fats mentioned include beeswax, shea butter, and rice wax.

3. The structure of double-layered coated zinc oxide particles as described in claim 1, wherein, The zinc oxide particles have a particle size greater than 100 nanometers.

4. A method for preparing a double-layer coated zinc oxide particle structure, applied to the double-layer coated zinc oxide particle structure as described in claim 1, the method comprising the following steps: (a) preparing polyhydroxystearic acid to mix with zinc oxide particles in an oil phase to form a surface-coated oleophilic interface layer, the surface-coated oleophilic interface layer being the first layer structure, and cooling the first layer structure; (b) preparing a natural wax material and controlling the temperature to 70 °C; (c) uniformly wetting the natural wax material on the outside of the first layer structure and coating it; (d) cooling the natural wax material to between 35 °C and 45 °C and cooling it, the cooling process crystallizing to form a film to form a second layer structure, thus completing the sealing of the zinc oxide particles.

5. An oil-phase preemulsified suspension composition applied to a double-layer coated zinc oxide particle structure as described in claim 1, wherein the oil-phase preemulsified suspension composition has a weight percentage concentration of 100, and the oil-phase preemulsified suspension composition comprises: Zinc oxide particles with a weight percentage concentration of 20±1; A first layer structure with a weight percentage concentration of 1 ± 0.1; a second layer structure with a weight percentage concentration of 5.5 ± 0.2; and a bulk matrix material with a weight percentage concentration of 73.5 ± 2. The zinc oxide particles, the first layer structure, the second layer structure, and the bulk matrix material are uniformly mixed together.

6. The oil-phase pre-emulsified suspension composition as described in claim 5, wherein, The material of the first layer structure is polyhydroxystearic acid.

7. The oil-phase pre-emulsified suspension composition as described in claim 5, wherein, The materials of the second layer structure include beeswax, shea butter, and rice wax.

8. The oil-phase pre-emulsified suspension composition as described in claim 7, wherein, The weight percentage concentration of the beeswax is 3±0.1, the weight percentage concentration of the shea butter is 2±0.1, and the weight percentage concentration of the rice wax is 1±0.

1.

9. The oil-phase preemulsified suspension composition as described in claim 5, wherein, The bulk matrix material is selected from one or any combination of microcrystalline wax, plant-derived squalane, coco-caprylate, mineral oil-free, silicone oil, nanoparticles, and hydrogenated lecithin.

10. The oil-phase pre-emulsified suspension composition as described in claim 9, wherein, The plant-derived squalane has a weight percentage concentration of 15±1, the Coco-Caprylate has a weight percentage concentration of 56.5±2, and the hydrogenated lecithin has a weight percentage concentration of 1.5±0.

1.

11. A pet- and baby-friendly non-toxic sunscreen product, applied to the double-layer coated zinc oxide particle structure as described in claim 1, wherein the pet- and baby-friendly non-toxic sunscreen product has a weight percentage concentration of 100, and comprises: An aqueous phase composition with a weight percentage concentration of 38±2%; an oil phase composition with a weight percentage concentration of 21±1%; a double-layered zinc oxide particle structure with a weight percentage concentration of 40±2%; a preservative with a weight percentage concentration of 0.5±0.1%; and vitamin E with a weight percentage concentration of 0.5±0.1%. The aqueous phase composition, the oil phase composition, the double-layered zinc oxide particle structure, the preservative, and the vitamin E are uniformly mixed together.

12. The pet- and baby-friendly non-toxic sunscreen product as described in claim 11, wherein, The aqueous phase composition comprises deionized water, glycerol, propylene glycol, xanthan gum, and citric acid solution.

13. The pet- and baby-friendly non-toxic sunscreen product as described in claim 12, wherein, The weight percentage concentration of the deionized water is 31.5±2, the weight percentage concentration of the glycerol is plant-derived and is 4±0.2, the weight percentage concentration of the propylene glycol is plant-derived and is 2±0.1, the weight percentage concentration of the xanthan gum is 0.2±0.1, and the weight percentage concentration of the citric acid solution is 0.3±0.

1.

14. The pet- and baby-friendly non-toxic sunscreen product as described in claim 11, wherein, The oil phase composition includes coconut alkyl ester, isopentyl laurate, vegetable emulsified wax, vegetable squalane, and titanium dioxide (non-nano titanium dioxide).

15. The pet- and baby-friendly non-toxic sunscreen product as described in claim 14, wherein, The weight percentage concentration of the coconut alkyl ester is 5±0.2, the weight percentage concentration of the isopentyl laurate is 4±0.1, the weight percentage concentration of the plant emulsified wax is 4±0.1, the weight percentage concentration of the plant squalane is 3±0.1, and the titanium dioxide is non-nano titanium dioxide with a weight percentage concentration of 5±0.

2.

16. The pet- and baby-friendly, non-toxic sunscreen product as described in claim 11, wherein, The preservative and vitamin E mentioned are of plant origin.

17. A method for preparing a pet- and baby-friendly non-toxic sunscreen product, applicable to the pet- and baby-friendly non-toxic sunscreen product as described in claim 12, comprising the following steps: (a) preparation of an aqueous phase composition and an oil phase composition; (b) mixing and emulsifying the aqueous phase composition and the oil phase composition; (c) cooling the mixture of the aqueous phase composition and the oil phase composition; (d) adding the double-layer coated zinc oxide particle structure to the mixture of the aqueous phase composition and the oil phase composition; (e) adding the preservative and the vitamin E to the mixture of the aqueous phase composition, the oil phase composition and the double-layer coated zinc oxide particle structure to obtain the pet- and baby-friendly non-toxic sunscreen product.

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