Multilayer Coating Film for Metallic Paint Lightness
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Solution Overview
Problem
Existing methods for forming metallic paint coatings result in insufficient lightness and chroma in highlights, along with high graininess and lack of darkness, due to the orientation of flake-effect pigments in the metallic base coating film.
Innovation Solution
A multilayer coating film formation method involving an effect pigment dispersion with water, surface adjusting agents, flake-effect pigments, and rheology control agents, applied to a substrate, followed by a colored transparent paint, achieving a total light transmittance of 20-70% at 400-700 nm, and optionally topped with a clear paint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional metallic base coating film is applied with flake-effect pigment, then the coating provides metallic effect, but the lightness in highlight is insufficient and the darkness is insufficient due to pigment orientation
Solution Approach 1:
The coating system is divided into multiple functional layers: a metallic base coating layer containing flake-effect pigment and a clear topcoat layer. This segmentation allows the base layer to provide metallic effect while the topcoat layer enhances light reflection and control, resolving the contradiction between achieving high lightness and controlling pigment orientation.
Solution Approach 2:
The invention uses a composite coating system combining metallic base paint with flake-effect pigment and clear topcoat. This composite structure allows the flake-effect pigment to provide metallic luster while the clear topcoat enhances highlight lightness through light reflection and refraction, simultaneously achieving both metallic effect and high lightness without requiring precise pigment orientation control.
2Object-generated harmful factors
If flake-effect pigment is applied in metallic base coating, then metallic effect is achieved, but graininess is high and darkness is insufficient
Solution Approach 1:
The flake-effect pigment is pre-dispersed in the metallic base paint before application, ensuring uniform distribution. The clear topcoat is then applied over this pre-prepared base layer, which already has optimized pigment dispersion. This preliminary action prevents graininess and ensures coating uniformity while maintaining the metallic effect.
Solution Approach 2:
The clear topcoat acts as an intermediary layer between the viewer and the flake-effect pigment in the base coating. This intermediate layer smooths out the visual appearance by providing a uniform refractive index medium, reducing the perception of graininess while allowing the metallic effect to shine through. It also enhances darkness by controlling light transmission.
3Device complexity
If multiple clear paint layers are applied as in PTL 1, then coating complexity increases, but lightness and chroma in highlight remain insufficient
Solution Approach 1:
Instead of applying multiple clear paint layers with similar properties, the invention changes the parameters by using a specifically formulated clear topcoat with optimized refractive index, thickness, and curing characteristics. This single layer with optimized parameters achieves superior highlight lightness and chroma compared to multiple conventional clear layers, reducing process complexity while improving performance.
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 produces a paint color with high lightness, chroma, low graininess, and excellent darkness in highlights, enhancing the visual appearance by optimizing the orientation and interaction of pigments.
Implementation Method 1
metallic paint colors, which have high lightness in highlight (near-specular reflection light)
Implementation Method 2
changes in lightness from highlight to bottom (in the oblique direction)
Implementation Method 3
applying a colored transparent paint to the effect pigment-containing coating film to form a colored transparent coating film having a total light transmittance at a wavelength of 400 nm to 700 nm of 20 to 70%
Data Source
AI summary
A method for forming a multilayer coating film comprising the steps of:applying, to a substrate, an effect pigment dispersion that comprises water, a surface adjusting agent, a flake-effect pigment, and a rheology control agent, and that has a solids content within the range of 0.5 to 10 mass % to form an effect pigment-containing coating film; andapplying a colored transparent paint to the effect pigment-containing coating film to form a colored transparent coating film having a total light transmittance at a wavelength of 400 nm to 700 nm of 20 to 70%.