Sun-screening agent with high-content titanium dioxide or zinc oxide and preparation method thereof

Abstract

The invention provides a sun-screening agent with high-content titanium dioxide or zinc oxide. The sun-screening agent with the high-content titanium dioxide or zinc oxide is prepared from the following components in parts by weight: 5 to 20 parts of hydrophobically modified titanium dioxide or zinc oxide, 0.2 to 2 parts of a crylic acid (ester) / beheneth-25 methacrylate polymer, 0.05 to 2 parts ofan alkaline agent, and 0.3 to 1 part of a preservative. The sun-screening agent provided by the invention has relatively high content of hydrophobic inorganic sun-screening particles, can reach a high SPF (Sun Protect Factor) value easily and has a refreshing skin feeling; because the use of an emulsifying agent is avoided, the sun-screening agent has more refreshing skin feeling and lower irritation, and is suitable to be applied to sun-screening cosmetics for sensitive skin.

Description

technical field [0001] In the field of cosmetics, the invention particularly relates to a sunscreen agent with high content of titanium dioxide or zinc oxide and a preparation method thereof. Background technique [0002] Titanium dioxide and zinc oxide of inorganic sunscreens are insoluble particles, which are dispersed in the water phase of cosmetics, and agglomeration will occur during application on the skin, thereby greatly reducing the sunscreen effect. Therefore, titanium dioxide or zinc oxide used in sunscreen cosmetics generally adopts hydrophobically modified nano-sized particles, which are then dispersed in the oil phase of the cosmetics. However, to prepare oil-in-water sunscreen cosmetics with a refreshing skin feel, an emulsifier is generally used to emulsify the powder slurry of titanium dioxide or zinc oxide to achieve the effect of evenly dispersing titanium dioxide or zinc oxide in the cosmetics, so that it can be evenly dipped in when applied. Pick. [0...

AI Technical Summary

Problems solved by technology

[0004] (1) The amount of titanium dioxide and zinc oxide should not be too high

Because hydrophobically modified nano-scale titanium dioxide or zinc oxide has a water-in-oil interfacial activity tendency, if the amount used is too high, it is very easy to phase inversion, so that the phase inversion of the oil-in-water system becomes a water-in-oil system, or direct demulsification and stratification , greatly reducing the system stability

[0005] (2) Using high content or high molecular weight emulsifiers for emulsification will lead to bad skin feeling

For the same reason, due to the strong water-in-oil tendency of hydrophobically modified titanium dioxide or zinc oxide particles, it is necessary to use a large number of emulsifiers with high HLB value or high molecular weight to overcome this tendency, and these emulsifiers are often very sticky. The skin feel of the whole oil-in-water sunscreen cosmetics becomes sticky, and even if a large amount of such emulsifiers are used, it is still very easy to phase invert or break when using high content of titanium dioxide or zinc oxide

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