Wet Coating Gloss Prediction Using Reflectance Measurement
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Solution Overview
Problem
The existing 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 solutions fail to accurately correlate wet optical properties with the final gloss due to solvent evaporation and light distortions in glass containers.
Innovation Solution
A device comprising a test substrate, a vessel for dispensing a flatting agent-free coating layer, an optical measurement mechanism, a gloss meter, and a computer system that measures and stores reflectance and gloss data, uses curve fitting to predict the gloss of a target coating by subtracting baseline reflectance from measured values and locating intersecting points on a graph.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional testing procedures are used to measure gloss of coating compositions, then measurement accuracy is achieved, but the manufacturing process is interrupted frequently and time is lost
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 of the traditional wait-and-measure approach, eliminating the need to interrupt manufacturing for repeated testing cycles. The system establishes a correlation between wet state optical properties and final gloss values, enabling real-time quality assurance without stopping production.
2Productivity
If wet optical property measurements are taken continuously, then real-time monitoring is achieved, but the correlation to final gloss becomes difficult due to solvent evaporation and crosslinking
Solution Approach 1:
The system performs the measurement at the optimal moment - immediately when the coating is applied in a wet state but before significant solvent evaporation or crosslinking occurs. This preliminary measurement captures the optical properties at a stable point in time, establishing an accurate baseline for correlation with final gloss values.
Solution Approach 2:
The patent addresses parameter changes by controlling the measurement timing to occur before the coating composition undergoes significant chemical or physical changes. By measuring in the wet state immediately after application, the system captures optical properties before solvent evaporation and crosslinking alter the coating's refractive index and other optical parameters, maintaining measurement-to-final-gloss correlation accuracy.
3Ease of operation
If color properties are measured in a clear glass container, then measurement is simplified, but accuracy is reduced due to light reflection and refraction distortions
Solution Approach 1:
Instead of measuring the coating in its final applied state on a substrate (which would be complex and time-consuming), the system creates a simplified copy model by applying the coating to a carrier strip. This copying approach allows optical property measurement in a controlled, simple geometry that is easy to handle while still maintaining accurate correlation to the final coating's gloss, avoiding the light distortion problems of glass container measurements.
4Productivity
If a circulating carrier strip system is used for measurement, then continuous measurement is enabled, but the device complexity increases
Solution Approach 1:
The carrier strip serves multiple functions: it provides a substrate for coating application, a stable platform for optical measurement, and a transport medium for moving the coating through the measurement zone. This multi-functionality reduces the need for separate systems for each function, thereby limiting the increase in overall device complexity while enabling continuous measurement capability.
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 real-time prediction of coating gloss, reducing batch-to-batch variability and manufacturing interruptions by accurately correlating wet optical properties with dried or cured coating gloss, thus expediting the manufacturing process.
Implementation Method 1
an optical measurement instrument to measure reflectance B 0 of said beam reflected from said flatting agent free layer L 0 at a preset angle of reflectance
Data Source
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AI summary
The present invention is directed to a device 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 device 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 device 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 device is most useful during the manufacture of coating compositions, such as automotive OEM and refinishes paints.