Effect Pigments Zinc Oxide Coating Weather Resistance
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Solution Overview
Problem
Existing effect pigments, particularly those with titanium dioxide or iron oxide layers, exhibit significant changes in properties due to external influences like light and water, leading to discoloration, embrittlement, and reduced mechanical and chemical stability, making them unsuitable for long-term outdoor applications.
Innovation Solution
The development of effect pigments with an outer coating comprising zinc oxide, hydroxide, or oxide hydrate, combined with metal oxides such as zirconium, silicon, or aluminium, and organic coupling agents, providing improved stability and resistance to environmental factors without affecting the chroma or luster of the pigments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If effect pigments are coated with conventional metal oxide layers (titanium dioxide, iron oxide), then the pigments achieve good orientation and distribution in surface coatings, but they show considerable changes in properties due to light and water exposure, leading to discoloration and reduced stability
Solution Approach 1:
The patent applies a composite outer coating consisting of multiple metal oxides (zinc oxide, zirconium oxide, silicon oxide, aluminium oxide) combined with organic coupling agents. This composite structure provides both protection against environmental factors (light, water) and maintains the desired optical properties, resolving the contradiction between stability and discoloration resistance
Solution Approach 2:
Organic coupling agents are introduced as intermediary substances between the metal oxide layers and the substrate. These coupling agents improve the compatibility and adhesion of the coating, while the specific composition (including zinc oxide) provides protection against UV radiation and water, preventing discoloration while maintaining reliability
2Ease of operation
If effect pigments are subjected to aftertreatment with polymer coatings, then the applicational properties are improved, but the pigments show reduced photostability and compatibility with the application medium
Solution Approach 1:
The patent changes the chemical composition parameters of the outer coating by using inorganic metal oxides (particularly zinc oxide, zirconium oxide) instead of organic polymers. This parameter change maintains ease of application while significantly improving photostability, as inorganic oxides are inherently more resistant to UV degradation than organic polymers
3Stability of the object's composition
If multi-layer metal oxide coatings are applied on top of each other, then the structural stability is improved, but the manufacturing complexity and number of processing steps increase
Solution Approach 1:
The patent combines multiple metal oxide components (zinc oxide, zirconium oxide, silicon oxide, aluminium oxide) and organic coupling agents into a single integrated outer coating layer. This merging approach maintains the protective benefits of multi-component systems while simplifying the manufacturing process, as all components are applied together in one coating step rather than as separate layers
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 new pigments demonstrate enhanced weather-resistance and stability, maintaining their color and luster, especially in outdoor applications, while being suitable for various media like paints, coatings, and plastics.
Implementation Method 1
effect pigments having an outer coating consisting of A) zinc oxide, hydroxide and/or oxide hydrate, B) at least one metal oxide, hydroxide and/or oxide hydrate... show improved stability... weather-resistance which is important for outdoor uses
Implementation Method 2
the action of external influences, such as light or water. This is evident from discoloration... improved stability... enhanced weather-resistance and stability, maintaining their color and luster
Implementation Method 3
outer coating comprising A) zinc oxide, hydroxide and/or oxide hydrate, B) at least one metal oxide, hydroxide and/or oxide hydrate, and C) at least one organic coupling agent
Data Source
AI summary
The present invention relates to effect pigments based on substrates having outer coating comprising metal oxide, hydroxide and/or oxide hydrate and at least one organic coupling agent.