Xanthene Dye Indicator for Non-Contact Curing Progress Detection
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Solution Overview
Problem
Existing indicator systems for coating processes fail to reliably display the curing progress of compositions containing isocyanate and isocyanate-reactive components without coloring the composition in the cured state, limiting their use in clear varnishes and other color-sensitive applications.
Innovation Solution
An indicator system using a dye with a xanthene skeleton, which changes color upon contact with the uncured composition and becomes colorless in the cured state, optionally applied to an inert carrier to ensure non-contact, colorless curing indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indicator dyes are added to curable compositions to show curing progress, then the curing level can be indicated, but the dye colors the cured composition, precluding use in clear varnishes
Solution Approach 1:
The patent applies parameter changes by utilizing dyes whose molecular structure and optical properties change during the curing process. The dye molecules transition from a colored state in the uncured composition to a colorless state in the cured composition, allowing curing indication without permanent coloration. This is achieved through chemical reactions that alter the dye's conjugated system or aggregation state.
Solution Approach 2:
The patent employs phase transitions in the dye molecules themselves, where the dye undergoes a chemical or physical transformation during curing. The dye transitions from a soluble, colored molecular form in the uncured state to an insoluble, colorless form in the cured state, enabling the indication function while eliminating the harmful coloration effect.
2Measurement precision
If dyes are used to indicate curing in compositions curing by radical polymerization, then color change indication is achieved, but the dyes cannot be used in compositions curing by polyaddition reaction due to potential reactions with reactive components
Solution Approach 1:
The patent introduces an intermediary substance or mechanism that mediates between the dye and the curable composition. This intermediary protects the dye from reacting with reactive components in polyaddition-curing compositions while still allowing the dye to indicate curing progress. The intermediary could be a protective group, a specific molecular structure, or a reaction mechanism that prevents unwanted side reactions.
3Device complexity
If simple color change indicators are used, then the indication method is simple, but the indicators do not provide reliable non-contact detection capability
Solution Approach 1:
The patent utilizes color changes as the primary indication mechanism, leveraging the human eye's sensitivity to color variations. The dye undergoes distinct color transitions during curing, providing reliable visual feedback without requiring complex detection equipment. This approach maintains simplicity while achieving reliability through the inherent sensitivity of optical detection.
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 system provides a reliable, non-contact method to determine the curing progress without altering the appearance of the coated surface, enabling safe further processing and increasing the efficiency of coating operations by allowing earlier subsequent steps.
Implementation Method 1
the at least one indicator dye has a first color after contact with the uncured composition and is colorless in the cured composition
Data Source
AI summary
The invention relates to an indicator system, a method for optically displaying the progress of curing a composition, the use of colourants with a xanthene skeleton to optically display the progress of curing compositions, a kit-of-parts, and a method for increasing the clock rate between a coating step and an additional, downstream processing step for objects.