Core-Shell Particle Actives for Long-Lasting Cosmetic Opacity
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Solution Overview
Problem
Cosmetic compositions with high pigment loadings for skin opacity often result in poor tactile sensory and unnatural whiteness, while existing solutions fail to provide long-lasting optical benefits due to time-dependent loss of optical properties after application.
Innovation Solution
A cosmetic composition featuring particle actives with a water-insoluble inorganic shell and a volatile liquid core, where the shell has a refractive index of 1.3 to 1.8 and the core has a refractive index of at least 1.2, combined with a cosmetically acceptable carrier containing less than 15% liquid oil, allowing for enhanced light scattering and increased optical benefits over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high pigment and colorant content is used to achieve skin opacity and blemish masking, then optical benefits are improved, but tactile sensory quality deteriorates
Solution Approach 1:
The pigment particles are segmented into core-shell structures with distinct functional zones: a hydrophobic core for oil compatibility and a hydrophilic shell for water compatibility and skin adhesion. This segmentation allows each part to optimize its function without compromising the other, enabling high pigment loading while maintaining tactile quality.
Solution Approach 2:
The invention uses composite particles combining hydrophobic and hydrophilic materials in a core-shell architecture. The hydrophobic core (e.g., titanium dioxide, zinc oxide) provides opacity, while the hydrophilic shell (e.g., silica, alumina) provides skin compatibility and tactile comfort. This composite structure resolves the contradiction between optical performance and tactile quality.
2Duration of action of stationary object
If high loading of opacifying particles is used to compensate for time-dependent loss of optical benefits, then duration of action is improved, but naturalness of appearance deteriorates
Solution Approach 1:
The hydrophilic shell is pre-applied to the hydrophobic core before application to skin. This preliminary structuring ensures that particles remain dispersed and do not aggregate during the drying process, maintaining natural appearance even at lower loadings while providing lasting optical benefits through controlled release mechanisms.
Solution Approach 2:
The invention changes the surface properties of particles by coating hydrophobic cores with hydrophilic shells, altering their interaction with skin and environment. This parameter change allows particles to maintain stability and optical benefits over time without requiring high loadings that would compromise natural appearance.
3Stability of the object's composition
If emulsion droplets coalesce and break up during drying, then film formation is improved, but optical benefits are lost
Solution Approach 1:
The hydrophilic shell acts as a flexible protective layer around the hydrophobic core, allowing the particle to adapt to film formation processes while maintaining its structural integrity and optical properties. This flexible shell prevents particle aggregation during drying, preserving both film quality and optical benefits.
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 composition provides long-lasting and evolving optical benefits, such as improved skin tone evening and blemish masking, by enhancing light scattering efficiency as the volatile liquid evaporates, resulting in increased opacity without the initial unnatural whiteness.
Implementation Method 1
allowing for enhanced light scattering and increased optical benefits over time... as the volatile liquid evaporates
Implementation Method 2
enhancing light scattering efficiency as the volatile liquid evaporates, resulting in increased opacity
Data Source
AI summary
A cosmetic composition is disclosed comprising particle active and cosmetically acceptable carrier comprising hydrophobic material, wherein the hydrophobic material comprises less than 15% liquid oil by weight of the composition. The particle active comprises (i) water-insoluble shell component comprising inorganic material and having a refractive index of from 1.3 to 1.8; and (ii) core component comprising volatile liquid and having a refractive index of at least 1.2.