Tabular Metal Oxide Skin Preparation for IR-UV Protection
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Solution Overview
Problem
Existing external skin preparations struggle to provide both effective protection against IR and UV rays while maintaining a natural appearance and good adhesion of makeup without stickiness.
Innovation Solution
The use of a tabular metal oxide with specific thickness and aspect ratio, combined with a UV absorbent or UV scattering agent, and a nonvolatile oil, to create a skin preparation that enhances IR and UV protection while minimizing visible light reflectance and ensuring a natural appearance and good makeup adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional IR protective agents containing titanium oxide powder and zinc oxide powder are used, then IR protection is provided, but the preparation causes skin whitening and gives an unnatural appearance
Solution Approach 1:
The patent changes the particle morphology parameter from spherical to tabular shape, and controls the thickness parameter within 30-360 nm range. This parameter change allows the metal oxide to selectively reflect IR rays while being transparent to visible light, resolving the contradiction between IR protection and natural appearance
Solution Approach 2:
The patent creates particles with anisotropic structure where the tabular shape provides different optical properties in different directions and wavelengths. The flat surfaces selectively interact with IR radiation while allowing visible light to pass through, achieving local quality differentiation that resolves the appearance contradiction
2Object-affected harmful factors
If conventional sunblock cosmetics are used, then UV protection is provided, but the preparation exhibits stickiness and poor makeup adhesion
Solution Approach 1:
The patent combines tabular metal oxide particles with specific organic UV absorbents in a composite formulation. This composite approach allows the inorganic particles to provide UV scattering and absorption while the organic components ensure proper skin feel and makeup adhesion, resolving the contradiction between UV protection and ease of operation
Solution Approach 2:
The patent optimizes the particle size and shape parameters of the tabular metal oxide to achieve a balance between protective function and cosmetic performance. The specific aspect ratio and thickness ranges are designed to minimize stickiness while maintaining UV protection efficacy
3Illumination intensity
If tabular metal oxide with small thickness is used, then transparency is improved, but IR protection is reduced
Solution Approach 1:
The patent identifies and optimizes the thickness parameter within a specific range (30-360 nm) that provides the optimal balance between transparency and IR protection. This parameter optimization ensures that the particles are thin enough to be transparent to visible light while maintaining sufficient thickness to reflect IR radiation effectively
Solution Approach 2:
The patent transitions from considering only particle size to considering particle thickness as a separate dimensional parameter. By controlling the thickness dimension specifically while maintaining tabular geometry, the invention achieves independent control over optical properties at different wavelengths, resolving the transparency-IR protection contradiction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The skin preparation achieves high-level IR protection, UV protection, and maintains a natural appearance without stickiness, providing excellent heat insulation and makeup adhesion.
Implementation Method 1
an IR transmission masking agent of a titanium oxide powder and a zinc oxide powder... which inhibits IR rays from reaching a tissue deeper than a skin tissue
Implementation Method 2
a UV absorbent (B)... excellent UV protective effect
Implementation Method 3
a UV scattering agent (C)... excellent UV protective effect
Data Source
AI summary
The present invention relates to [1] an external skin preparation containing a tabular metal oxide (A) having a thickness of 30 to 360 nm and an aspect ratio of 50 to 300, and a UV absorbent (B) in a ratio [(A)/(B)] by mass of 0.1 to 5; [2] an external skin reparation containing the tabular metal oxide (A), a UV scattering agent (C) and a nonvolatile oil (D) in a ratio [(A)/(C)] by mass of 0.1 to 18; and [3] a method for protecting skin from IR rays and UV rays by applying the external skin preparation to skin.