Copper Patina Polymer Dispersion Adhesion
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Solution Overview
Problem
Existing methods for artificial patination of copper surfaces either fail to achieve permanent adhesion, are not UV-resistant, or limit color variability and weatherability, while naturally weathered copper products require a long time to develop a dense patina layer.
Innovation Solution
A method involving chemical patination of copper surfaces to form a porous layer of copper salts, followed by application of an aqueous polymer dispersion with pigments that penetrates and solidifies within the patina, enhancing adhesion, UV resistance, and color variability without blocking water vapor diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If organic paint layers are applied to copper surfaces, then color variability is achieved, but adhesion is poor and UV resistance is lost
Solution Approach 1:
The invention uses a composite structure consisting of an inorganic patina layer (copper salts like brochantite, paratacamite, or malachite) combined with an organic polymer dispersion coating. The inorganic layer provides UV resistance and adhesion to the copper substrate, while the organic polymer layer provides color variability and weather protection, creating a synergistic composite material system that resolves the contradiction between color flexibility and durability.
Solution Approach 2:
The patina layer is formed as a porous structure with controlled pore size and distribution. This porous structure allows the subsequent polymer dispersion to penetrate and anchor within the patina matrix, significantly improving adhesion. The porosity also allows water vapor diffusion while providing a large surface area for pigment incorporation, thus achieving both strong bonding and color variability.
2Reliability
If chemical patination is used to form dense patina layers, then adhesion and UV resistance are improved, but color variability is limited
Solution Approach 1:
The invention introduces an intermediary polymer dispersion coating that acts as a mediator between the chemically formed patina layer and the desired color variations. The polymer dispersion contains pigments that can be adjusted to achieve different colors, while the polymer matrix itself provides a flexible, weather-resistant medium that does not restrict the underlying patina's adhesion or UV resistance properties.
Solution Approach 2:
The invention enables parameter changes in the polymer dispersion coating, specifically in pigment concentration, pigment type, and polymer composition. By varying these parameters, a wide range of colors can be achieved on top of the stable, adherent patina base, thus decoupling the adhesion function (handled by the patina) from the color function (handled by the polymer coating).
3Reliability
If protective coatings are applied to patinated surfaces, then durability is improved, but natural weathering capability is blocked
Solution Approach 1:
The polymer dispersion coating is specifically designed to form a porous structure rather than a dense, impermeable film. The pores allow water vapor to diffuse through the coating and reach the copper substrate, enabling continued natural weathering and patina formation. At the same time, the polymer matrix provides protection against mechanical damage, UV degradation, and pollution, thus achieving durability without blocking weathering.
Solution Approach 2:
The coating is applied as a thin, flexible polymer dispersion layer that conforms to the patina surface topology. This thin film structure provides protection while maintaining permeability to water vapor, unlike thick, rigid protective coatings that would block weathering. The flexibility allows the coating to accommodate surface changes during continued weathering without cracking or delaminating.
4Reliability
If natural weathering is allowed to proceed, then authentic patina character is achieved, but production time is excessive
Solution Approach 1:
The invention applies preliminary chemical treatment to copper surfaces to accelerate patina formation. By exposing copper to controlled chemical environments (such as sulfur-containing atmospheres or aqueous solutions), a dense patina layer forms in hours or days rather than years. This preliminary action creates an authentic-looking patina base that can then be enhanced with the polymer dispersion coating, dramatically reducing production time while maintaining authenticity.
Solution Approach 2:
The invention changes the parameters of the weathering process by controlling temperature, humidity, chemical composition, and exposure time in an accelerated weathering chamber. These parameter changes enable the formation of authentic patina structures (copper sulfate, copper carbonate, etc.) in a fraction of the time required for natural outdoor weathering, thus resolving the contradiction between authenticity and production efficiency.
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 method allows for high color variability and maintains the surface's weatherability, improving handling and durability while ensuring the patina remains visually similar to natural patina, with enhanced UV resistance and reduced health and corrosion risks.
Implementation Method 1
a patina layer is created by reacting one or more chemicals with the copper surface under special conditions
Implementation Method 2
an additional aqueous polymer dispersion is applied to the patinated surface. This polymer dispersion penetrates into the areas of the porous patina near the surface and, after drying, leads to cavities or pores near the surface being solidified with an organic mass
Implementation Method 3
Together with the patina, the polymer dispersion forms a water diffusion-permeable compound and not a closed, covering lacquer layer
Data Source
AI summary
The method comprises bringing a product in contact with a patination solution to form a patina layer, applying an aqueous polymer dispersion to the formed patina layer, and adding the patination solution and/or aqueous polymer dispersion pigments. Pigments other than the patination solution are added as polymer dispersion. A concentration of the pigments in the patination solution differs from a concentration of the pigments in the polymer dispersion. The patination solution added pigments do not form the patina layer. The method comprises bringing a product in contact with a patination solution to form a patina layer, applying an aqueous polymer dispersion to the formed patina layer, and adding the patination solution and/or aqueous polymer dispersion pigments. Pigments other than the patination solution are added as polymer dispersion. A concentration of the pigments in the patination solution differs from a concentration of the pigments in the polymer dispersion. The patination solution added pigments do not form the patina layer. The aqueous polymer dispersion penetrates a water vapor diffusion-transmissive composite into ranges near a surface of a porous patina, and is dried with the patina formation. The aqueous polymer dispersion (1-15 g/m 2>) is applied to the patinated surface with a solid content of 0.34-5 g/m 2> in a dried state. A concentration of admixture of pigments and the aqueous polymer dispersion is 5-10 wt.% based on nonionic and anionic wetting agents of an inorganic pigment dispersions used in an aqueous paint on acrylate. The method utilizes phenol, alkyl, ethoxylate and formaldehyde free pigment dispersion. The pigment dispersion comprises 50-70% of the pigments. An independent claim is included for a product made from copper or its alloy.