Spherical Pigment Coating for Natural Skin Appearance

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Solution Overview

Problem

Existing cosmetic pigments based on spherical particles, such as SiO2 spheres, suffer from high scattering power, leading to an unnatural appearance on the skin and limited skin feel, while also being time-consuming and expensive to process for dispersion and color consistency.

Innovation Solution

Development of spherical pigments with diameters between 0.1-100 μm, coated with agglomerates like ZrO2, ZnO, Al2O3, TiO2, Fe2O3, Fe3O4, or BaSO4, and optionally a second layer of metal oxides or Prussian blue, which reduce scattering and enhance skin feel and dispersibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If spherical SiO2 particles are used as cosmetic fillers, then they provide good skin feel and natural appearance, but they exhibit high scattering power leading to unnatural appearance and shine

Engineering Contradiction:
Improveskin feelVSAvoidscattering power
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent divides the coating into multiple layers: a first layer of metal oxide particles (0.5-100 nm) that provides scattering control, and a second layer of larger metal oxide particles (1-10 μm) that reduces overall scattering. This segmented structure allows each layer to contribute differently to the optical properties, achieving both natural appearance and reduced shine

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different particle sizes and materials to different layers of the coating. The first layer uses fine particles (0.5-100 nm) for uniform coverage and skin feel, while the second layer uses coarser particles (1-10 μm) for light scattering control. This local differentiation of particle properties optimizes both aesthetic and functional performance

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If metal oxide layers with small particles (0.5-100 nm) are used to cover carrier spheres, then uniform arrangement is achieved, but individual particles form strong scattering centers causing shine and unnatural appearance

Engineering Contradiction:
Improveuniform arrangementVSAvoidshine
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent transitions from a single-layer coating to a multi-layer coating structure, adding a dimensional aspect to the coating architecture. The first layer provides uniform base coverage, while the second layer adds a new dimension of particle size control to manage scattering and eliminate shine

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent creates a composite coating structure combining two different metal oxide particle systems with distinct size ranges. This composite approach allows the fine particles to provide uniform coverage while the coarser particles control the optical scattering, achieving both manufacturing precision and aesthetic quality

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If pigments are ground and pretreated for dispersion, then color consistency is improved, but the process becomes time-consuming and expensive

Engineering Contradiction:
Improvecolor consistencyVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary coating of the spherical particles with metal oxide layers during the particle formation process itself, rather than requiring separate grinding and dispersion steps afterward. This preliminary action ensures uniform color distribution and consistent optical properties are achieved during manufacturing, eliminating time-consuming post-processing steps

Inventive Principle:
Principle #10Preliminary action

4Object-generated harmful factors

If spherical particles with diameter 0.1-100 μm are coated with agglomerates, then scattering power is reduced and natural appearance is achieved, but coating complexity increases

Engineering Contradiction:
Improvescattering powerVSAvoidcoating structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent systematically varies key parameters of the coating: particle size (0.5-100 nm for first layer, 1-10 μm for second layer), material composition (different metal oxides), and layer thickness. By controlling these parameters, the patent achieves reduced scattering and natural appearance while managing coating complexity through defined specifications

Inventive Principle:
Principle #35Parameter changes

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 pigments provide a natural skin appearance, improved skin feel, better dispersibility, adjustable hiding power, and enhanced application properties, including increased viscosity and spreadability, while simplifying the production process.

Implementation Method 1

The fillers known from the prior art based on SiO 2 spheres... show the disadvantage that they have too high a scattering power

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The light is reflected on the layer surface, causing shine

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2316891B1Pigments
Publication Date: 2014.02.26 MERCK PATENT GMBH

AI summary

The present invention relates to inorganic spherical pigments based on spherical particles with a particle diameter of 0.1 - 100 µm and coated on the surface with agglomerates selected from the group consisting of ZrO2, ZnO, Al2O3, TiO2, Fe2O3, Fe3O4, FeOOH and BaSO4 or mixtures thereof, and optionally covered with a further layer (2nd layer) of a metal oxide, color lake or Prussian blue, as well as their use in paints, varnishes, printing inks, security printing inks, plastics, ceramic materials, glass, in cosmetic formulations, as tracers, as fillers and for the production of pigment preparations and dry preparations.