Wet Layer Reflectance for Low Gloss Coating Prediction
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Solution Overview
Problem
Current methods for predicting the gloss of low gloss coatings are time-consuming and cumbersome, as they require repeated testing of coating compositions on substrates, and existing methods to measure wet optical properties do not accurately correlate with the final dried or cured coating gloss due to solvent evaporation and crosslinking, as well as light distortions from clear glass containers.
Innovation Solution
A process involving dispensing a uniform layer of coating composition on a test substrate, measuring reflectance and gloss, storing data, and using curve fitting to predict the gloss of a target coating by determining the effect of flatting agents, allowing for real-time prediction without the need for repeated testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional testing procedures are used to measure gloss of coating compositions, then accurate gloss measurement can be obtained, but the process is time-consuming and causes frequent interruptions in manufacturing
Solution Approach 1:
The patent applies preliminary action by measuring the optical properties of the wet coating layer immediately after application, before the coating dries or cures. This allows gloss prediction to be made in advance without waiting for the traditional drying and measurement process, thereby eliminating manufacturing interruptions while maintaining measurement accuracy through subsequent correlation with actual gloss values.
Solution Approach 2:
The patent creates a correlation model that copies the relationship between wet layer optical properties and final dried coating gloss. By measuring the wet layer and using the established correlation, the system predicts the final gloss value without requiring actual drying and measurement, thus saving time while maintaining measurement precision.
2Loss of time
If wet optical property measurements are taken to predict gloss, then measurement time is reduced, but accuracy is compromised due to solvent evaporation and crosslinking changes
Solution Approach 1:
The patent implements feedback by measuring the optical properties of multiple wet layers with different known gloss values, then using this data to establish a correlation model. This feedback loop allows the system to account for the dynamic changes occurring during solvent evaporation and crosslinking, improving prediction accuracy while maintaining the time advantage of wet measurements.
Solution Approach 2:
The patent applies parameter changes by measuring optical properties at specific time points during the coating process and using correlation factors that account for solvent evaporation and crosslinking rates. By adjusting these parameters based on the specific coating composition and environmental conditions, the system maintains measurement precision despite the ongoing chemical and physical changes in the wet layer.
3Ease of operation
If clear glass containers are used to store coating composition for measurement, then measurement process is simplified, but light reflection and refraction distort the measurements
Solution Approach 1:
The patent extracts the coating composition from the confining clear glass container and applies it as a wet layer on a flat substrate for measurement. This removes the source of light reflection and refraction distortions caused by the container walls, thereby improving measurement precision while maintaining operational simplicity through the straightforward layer application and measurement process.
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
Enables accurate and efficient prediction of coating gloss, reducing batch-to-batch variability and manufacturing interruptions by correlating reflectance data with actual gloss measurements, thus optimizing the production process for low gloss coatings like automotive paints.
Implementation Method 1
projecting on the L0 layer a beam of light of a preset intensity at a preset angle of incidence from a light source; measuring B0 reflectance of the beam reflected from the L0 layer at a preset angle of reflectance by an optical measurement instrument
Data Source
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AI summary
The present invention is directed to a process for process for predicting gloss of a coating resulting from a wet layer of a low gloss coating composition, such as automotive OEM or refinish paint. The process includes measuring reflectance of the layer of the coating composition applied over a test substrate and then allowing the layer to dry and/or cure into a coating. Thereafter, its gloss is measured with a gloss meter. The process is repeated with varying amounts of one or flatting agents added to the composition and the reflectance vs. gloss is plotted on a graph and by using a curve fitting equation a gloss prediction curve is obtained. By measuring the reflectance of a wet layer of a target low gloss coating composition the gloss of a coating that would result from such a layer is then predicted by using the gloss prediction curve. The process is most useful during the manufacture of coating compositions, such as automotive OEM and refinishes paints.