SiO2 Interference Pigments With Stable Bluish-Red Color
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Solution Overview
Problem
Existing interference pigments exhibit a strong orange-red color effect at steep viewing angles and high opacity, leading to a naturally decreasing interference color at shallow angles, and are not suitable for vegan applications.
Innovation Solution
SiO₂ platelets coated with alpha-Fe₂O₃ crystallites of defined size, providing a brilliant bluish-red hue and high opacity, with low angular dependence of the color impression, suitable for diverse applications including cosmetics and paints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If SiO2 platelets are coated with metal oxide layers to create interference pigments, then the pigments exhibit high opacity and strong orange-red color effect at steep viewing angles, but the interference color intensity naturally decreases at shallow viewing angles and orange or dark brown down-flop is observed
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating layer by using alpha-Fe2O3 crystallites with specific size ranges (0.5-5 μm average diameter) and controlled crystal structure. This parameter optimization ensures that the absorption color remains bluish-red across all viewing angles while maintaining high opacity, eliminating the orange or dark brown down-flop observed in prior art.
Solution Approach 2:
The patent creates a composite material structure by coating SiO2 platelets with alpha-Fe2O3 crystallites. This composite approach combines the interference properties of the transparent SiO2 substrate with the absorption properties of the iron oxide crystallites, achieving both high opacity and consistent bluish-red coloration across different viewing angles.
2Manufacturing precision
If the interference pigment is designed to maintain color saturation at all viewing angles, then the absorption color must be brilliant and visible even at shallow angles, but this requires precise control of crystallite size and composition
Solution Approach 1:
The patent specifies precise parameter ranges for the alpha-Fe2O3 crystallites, including particle size (0.5-5 μm average diameter) and layer thickness (5-50 μm). These controlled parameters enable consistent optical properties across all viewing angles while providing clear manufacturing guidelines that balance precision requirements with practical producibility.
3Adaptability or versatility
If conventional interference pigments are used in cosmetic formulations, then they provide color effects, but they are not suitable for vegan applications
Solution Approach 1:
The patent replaces animal-derived carmine pigments with synthetically produced alpha-Fe2O3 crystallite-coated SiO2 platelets. This substitution uses inorganic materials that are vegan-compatible while maintaining or enhancing the desired color effects and optical properties for cosmetic applications.
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 maintain a pure bluish-red absorption color across all viewing angles, offering high opacity and color saturation, temperature stability, and compatibility with various media, including vegan formulations.
Implementation Method 1
a combination of interference and absorption color
Implementation Method 2
a combination of interference and absorption color
Data Source
AI summary
The present invention relates to interference pigments based on SiO2 platelets coated with alpha-Fe2O3 crystallites, and their use, in particular in paints, varnishes, industrial and automotive coatings, ceramic materials, plastics and cosmetic formulations.