Copper Pigment Dual-Layer Coating for Ion Release
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Solution Overview
Problem
Copper-containing metal pigments release copper ions, leading to undesirable effects such as color changes and gelation in applications like nail polish, due to the oxidation of Cu(I) to Cu(II) ions, which are not effectively prevented by existing coatings.
Innovation Solution
Platelet-shaped copper-containing metal pigments with an elemental copper content of at least 50% by weight, coated with a chemically non-reactive metal oxide layer and a plastic layer, where the weight ratio of the metal oxide to plastic layer is between 1:2 to 1:20, effectively encapsulating copper ions and preventing their release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If copper-containing metal pigments are used to achieve color effects, then aesthetic appearance is improved, but copper ion release causes color changes and gelation
Solution Approach 1:
The coating is divided into multiple functional layers: a metal oxide layer (SiO2, Al2O3, TiO2, etc.) that provides chemical stability and prevents copper ion release, and an organic polymer layer that provides mechanical protection and compatibility with coating formulations. This segmented structure allows each layer to address specific problems independently.
Solution Approach 2:
The invention uses composite coating materials combining inorganic metal oxides with organic polymers. The metal oxide layer provides chemical inertness and stability, while the organic polymer layer provides compatibility with coating formulations and additional protective properties. This composite approach resolves the contradiction between maintaining copper pigment functionality and preventing harmful ion release.
2Object-generated harmful factors
If existing single-layer coatings are applied to prevent copper ion release, then some protection is achieved, but color stability and opacity are compromised
Solution Approach 1:
The dual-layer coating structure separates the functions of copper ion prevention (metal oxide layer) and color/optical property maintenance (organic polymer layer), allowing each layer to be optimized for its specific function without compromising the other.
Solution Approach 2:
The metal oxide layer acts as an intermediary barrier between the copper pigment core and the external environment, preventing direct contact and ion release while maintaining optical properties. The organic polymer layer then acts as a secondary intermediary providing additional protection and formulation compatibility.
3Object-generated harmful factors
If chemically reactive binder coatings are used to encapsulate copper pigments, then copper ion release is reduced, but the coatings gel due to reaction with copper ions
Solution Approach 1:
The metal oxide layer creates a chemically inert environment around the copper pigment, preventing reactive interactions between copper ions and the organic polymer coating. This inert barrier eliminates the gelation problem while maintaining encapsulation effectiveness.
Solution Approach 2:
The metal oxide layer serves as a chemically inert intermediary that physically separates the reactive copper pigment from the organic polymer coating, preventing harmful chemical reactions while maintaining the protective encapsulation function.
4Object-generated harmful factors
If thick coating layers are applied to prevent copper ion release, then protection is improved, but opacity and application properties deteriorate
Solution Approach 1:
The protective function is segmented across two thin layers rather than one thick layer, achieving effective copper ion prevention with minimal total coating thickness. The metal oxide layer provides the primary barrier function in a thin configuration, while the organic polymer layer provides additional protection without significant thickness increase.
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 two-layer coating structure significantly reduces copper ion release, maintaining application properties like opacity and color stability during baking processes, and extends storage stability in nail polishes beyond six months without discoloration.
Implementation Method 1
coated with a chemically non-reactive metal oxide layer and a plastic layer, where the weight ratio of the metal oxide to plastic layer is between 1:2 to 1:20, effectively encapsulating copper ions and preventing their release
Implementation Method 2
The two-layer coating structure significantly reduces copper ion release, maintaining application properties like opacity and color stability during baking processes
Data Source
AI summary
The invention relates to copper-containing metal pigments, wherein the copper-containing metal pigments have a content of elemental copper of at least 50 wt% relative to the total weight of the uncoated copper-containing metal pigment, wherein the copper-containing metal pigments comprise at least one enveloping metal oxide layer and at least one enveloping chemically non-reactive plastic layer, wherein the sum of the contents of the at least one chemically non-reactive plastic layer and of the at least one metal oxide layer ranges between 10 and 50 wt% relative to the weight of the uncoated metal pigment, and the weight ratio of the at least one metal oxide layer to the at least one chemically non-reactive plastic layer ranges between 1:2 and 1:20. The invention further relates to a method for the production of said pigments and to the use thereof.