Multi-Layer Coating Film with Controlled Light Reflectance and Transmittance
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Solution Overview
Problem
Existing methods for forming multi-layer coating films, such as candy color coatings for automobiles, face challenges with color unevenness and non-uniform film design due to variations in film thickness, leading to reduced production efficiency and suboptimal color depth and brightness.
Innovation Solution
A process involving the application of a metallic base coating composition with both coloring and luster pigments, followed by a color base coating composition without luster pigments, and then a clear coating composition, with simultaneous heating and curing to achieve specific light reflectance and transmittance values, ensuring high saturation, brightness, and color depth while minimizing film thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strict control of coating conditions is implemented to suppress variations in film thickness, then color unevenness is reduced, but production efficiency decreases
Solution Approach 1:
The invention changes the optical parameters of the coating layers by selecting specific pigments with defined light reflectance and transmittance characteristics. The metallic base coating film is designed to reflect 45-50% of light in the 650-700 nm wavelength range, while the color base coating film is designed to transmit 50-70% of light in the same range. This parameter optimization allows the system to achieve uniform color appearance without requiring strict control of film thickness variations.
2Manufacturing precision
If film thickness variations are suppressed to achieve uniform film design, then color uniformity improves, but coating process complexity increases
Solution Approach 1:
The invention assigns different local qualities to different coating layers. The metallic base coating layer contains both luster pigment and coloring pigment with specific light reflectance properties, while the color base coating layer contains only coloring pigment with specific light transmittance properties. This differentiation of local qualities in each layer allows the system to achieve overall color uniformity through the combined optical effects rather than through uniform thickness control across all layers.
3Reliability
If a color clear coating composition is used to form candy color coating film, then color depth is improved, but color unevenness and color dulling occur frequently
Solution Approach 1:
The invention uses a composite coating structure with two distinct layers: a metallic base coating layer containing luster pigment and coloring pigment, and a color base coating layer containing only coloring pigment. This composite structure replaces the conventional single-layer color clear coating approach. The metallic base layer provides both color and metallic effect, while the color base layer enhances color depth through selective light transmission, achieving reliable color depth without the color unevenness and dulling problems associated with conventional color clear coatings.
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 process results in a multi-layer coating film with high saturation, brightness, and excellent color depth, reducing color unevenness and improving production efficiency by controlling light reflectance and transmittance within specific wavelength ranges.
Implementation Method 1
a single layer of the metallic base coating film obtained by heating and curing of the metallic base coating film in the step (1) has a light reflectance of from 45 to 50% in a wavelength range of 650 to 700 nm and a light reflectance of not more than 20% in wavelength ranges of 410 to 440 nm and 510 to 590 nm
Implementation Method 2
a single layer of the color base coating film obtained by heating and curing of the color base coating film in the step (2) has light transmittance of from 50 to 70% in a wavelength range of 400 to 700 nm, light transmittance of from 88 to 92% in a wavelength range of 650 to 700 nm and light transmittance of from 20 to 60% in wavelength ranges of 410 to 440 nm and 510 to 590 nm
Implementation Method 3
simultaneously heating and curing the metallic base coating film, the color base coating film and the clear coating film to form a multi-layer coating film
Data Source
AI summary
The purpose of the present invention is to obtain a method for forming an excellent multi-layer coating film of high chroma and brightness and a rich color. With the method, color mottling does not occur easily in the coating film and the design obtained is homogeneous even without strict control of variations in film thickness during coating. The method for forming the excellent multi-layer coating film comprises: forming a metallic base coating film on the surface of the object to be coated by applying a metallic base coating containing a shiny material; then forming a color base coating film by applying a color base coating; subsequently forming a clear coating film by applying a clear coating on the color base coating film; and heat-curing the metallic base coating film, the color base coating film and the clear coating film obtained. In the method, the light reflectance of the metallic base coating film is in a specified range and the light transmittance of the single color base coating film obtained by heat-curing the color base coating film as a single film is adjusted to a specified range.