Color Changing Caulk with pH Indicator

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Solution Overview

Problem

Current caulking compositions lack a reliable method to indicate when they have sufficiently cured, making it difficult to determine the appropriate time for applying surface treatments without damaging the caulk.

Innovation Solution

A color-changing caulking composition that uses a pH indicator, such as phenolphthalein, which changes color as the caulk cures, signaling when it has formed a skin thick enough to support surface treatments, while maintaining elastomeric properties and being free of plasticizers to reduce VOCs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If a pH indicator is added to indicate cure completion, then the ability to detect cure status is improved, but the composition complexity increases

Engineering Contradiction:
Improvecure status detectionVSAvoidcomposition complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent applies color change as a visual indicator system. A pH indicator (such as phenolphthalein) is incorporated into the caulk composition, which changes color in response to pH changes that occur during the curing process. This provides an intuitive, easy-to-observe signal that eliminates the need for complex testing equipment or procedures to determine cure status.

Inventive Principle:
Principle #32Color changes

2Stability of the object's composition

If the caulk remains flexible after cure, then the elastomeric behavior is improved, but the structural stability may be reduced

Engineering Contradiction:
Improveelastomeric behaviorVSAvoidstructural stability
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent utilizes parameter changes in the polymer matrix to achieve both flexibility and stability. By carefully selecting and formulating the polymer components and their ratios, the composition maintains elastomeric properties (flexibility, elasticity) while achieving sufficient structural stability for sealing applications. The pH indicator system also undergoes parameter changes (color) that correlate with the curing progression, providing visual feedback without affecting the mechanical properties.

Inventive Principle:
Principle #35Parameter changes

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 color-changing caulk composition effectively indicates cure completion by shifting from pink to white, ensuring the caulk is ready for surface treatments within one to four hours, maintaining stability and functionality for caulking or sealing purposes.

Implementation Method 1

A color-changing caulking composition that uses a pH indicator, such as phenolphthalein, which changes color as the caulk cures

Methodology Applied
Scientific EffectpH indicator color change: Photochromism

Data Source

PatentUS9040612B2Color changing caulk
Publication Date: 2015.05.26 RED DEVIL INC

AI summary

A caulk composition having a first color upon application and a second color upon formation of a skin, wherein said skin is suitable for application of a surface treatment.