Interference Pigments for Skin Protection
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Solution Overview
Problem
Current sun care and cosmetic products primarily focus on UVB and UVA protection, neglecting the impact of visible light (VIS) and near-infrared radiation (IR-A), which contribute to skin damage and photoaging, and existing inorganic pigments like TiO2 affect the skin feel and texture.
Innovation Solution
Development of interference pigments with platelet-shaped substrates coated with four high refractive layers, specifically SnO2 and TiO2, providing protection against VIS, HEV, and IR-A radiation while maintaining a natural skin feel and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If TiO2 pigment is added to improve light protection properties, then protection against UV radiation is improved, but skin feel and texture are worsened, and color intensity and gloss are reduced
Solution Approach 1:
The interference pigment is segmented into multiple thin layers (typically 3-7 layers) with alternating high and low refractive indices, each layer being only a few nanometers to a few tens of nanometers thick. This segmentation allows the pigment to provide broad-spectrum protection while maintaining optical properties and skin feel, as the layered structure interferes with harmful radiation through constructive and destructive interference patterns rather than through bulk absorption that would affect skin texture.
Solution Approach 2:
The interference pigment comprises a composite structure with a substrate (such as mica or glass flake) coated with multiple layers of materials having different refractive indices (e.g., TiO2, SiO2, ZrO2, Al2O3). This composite layered structure combines the protective properties of high-refractive-index materials with the optical interference effects, achieving UV, visible, and IR protection without the negative effects of bulk TiO2 pigment on skin feel and color.
2Object-affected harmful factors
If inorganic pigment is added to protect against UV radiation, then light protection is improved, but color intensity and gloss effect are reduced
Solution Approach 1:
The interference pigment utilizes optical interference to produce structural colors that change with viewing angle and illumination conditions. By controlling the thickness and refractive indices of the layers, the pigment can produce intense, pure colors with high gloss without relying on pigment concentration. The interference effects create iridescent or pearlescent color effects that are inherently more intense and luminous than conventional pigments.
Solution Approach 2:
The optical properties of the interference pigment are controlled by precisely adjusting parameters such as layer thickness (typically 5-50 nm per layer), refractive index contrasts, and layer sequences. By changing these parameters, the pigment can be tuned to provide specific color effects, protection spectra, and gloss levels, achieving both high color intensity and broad-spectrum protection simultaneously.
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 interference pigments offer pure interference colors, excellent skin feel, and effective protection against IR-A, VIS, and HEV radiation, enhancing skin health and cosmetic product performance.
Implementation Method 1
interference pigments based on platelet-shaped substrates with a defined particle size and coated with four high refractive layers
Implementation Method 2
protect the skin against VIS, HEV and IR-A
Implementation Method 3
interference pigments based on platelet-shaped substrates with a defined particle size and coated with four high refractive layers
Data Source
AI summary
The present invention relates to interference pigments based on platelet-shaped substrates which are coated with at least four high refractive layers and to the use thereof, inter alia in paints, coatings, printings inks, plastics and in particular in cosmetic formulations. The interference pigments show a moderate chroma and can be used as effect pigments, as filler pigments and as protection agent against near infrared radiation, VIS and high energy light.