Gas-Sensitive Acid Warning Coating With Reversible Color Change

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Solution Overview

Problem

Existing acid warning coatings are not environment-friendly, prone to decomposition in the presence of strong acids, and lack effective color-changing mechanisms, leading to safety risks and high costs due to reliance on solvent-based coatings and foreign imports.

Innovation Solution

A solvent-free gas-sensitive coating comprising a strong acid-resistant resin, a special color-changing agent treated white carbon black, and auxiliary components, which undergoes rapid and reversible color change upon exposure to volatile acids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If solvent-based coatings are used for acid detection, then the coating can be applied and provides color change function, but it releases volatile organic compounds and pollutes the air

Engineering Contradiction:
Improveair pollution from volatile organic compoundsVSAvoidcoating application process
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent changes the fundamental parameter of the coating system by transitioning from solvent-based to solvent-free formulation. The coating comprises polymeric resin, color-changing agent, and other components in a solvent-free matrix, eliminating volatile organic compound emissions while maintaining coating applicability and acid detection functionality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating material combining polymeric resin with color-changing agents (such as halochromic dyes or pH-sensitive materials) in a solvent-free system. This composite structure provides both the protective coating function and the acid detection function through integrated material design

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If polyurethane resin is used in the coating, then the coating can be applied easily, but it decomposes and falls off when encountering strong acids

Engineering Contradiction:
Improvecoating applicationVSAvoidcoating resistance to strong acids
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical resistance parameter by selecting polymeric resins with high acid resistance properties, such as epoxy resins, phenolic resins, or fluorinated polymers, replacing or supplementing polyurethane resin to maintain both applicability and strong acid resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite resin systems combining polymeric resin with acid-resistant inorganic materials or cross-linking agents to enhance the coating's chemical stability and adhesion under strong acid conditions while maintaining ease of application

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If existing acid warning coatings are used, then color change function is provided, but the color change is not obvious or response time is long

Engineering Contradiction:
Improvecolor change detection functionVSAvoidcolor change obviousness and response speed
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies halochromic dyes or pH-sensitive color-changing agents that exhibit rapid and obvious color transitions upon acid exposure. The color-changing agent is selected and formulated to provide high contrast color change (e.g., from yellow to red or from colorless to pink) with response time under 1 second, ensuring clear visual detection

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent optimizes the physical and chemical parameters of the color-changing agent, including particle size, concentration, and chemical structure, to achieve rapid response time and obvious color change. The formulation adjusts the sensitivity and response characteristics of the color-changing component to detect acid leakage quickly and clearly

Inventive Principle:
Principle #35Parameter changes

4Reliability

If imported acid warning coatings are used, then detection function is available, but the cost is high and supply cycle is long

Engineering Contradiction:
Improveacid detection functionVSAvoidcost and supply availability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs cost-effective, readily available raw materials including common polymeric resins, commercially available color-changing agents, and standard additives, replacing expensive imported coating components. The formulation uses locally sourced materials to reduce cost and eliminate supply cycle delays while maintaining effective acid detection functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite coating formulation using locally available materials that combines polymeric resin with domestically produced or easily obtainable color-changing agents and additives, achieving cost reduction and supply chain independence while maintaining reliable acid detection performance

Inventive Principle:
Principle #40Composite materials

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 coating provides quick, obvious, and reversible color change, suitable for repeated use, and is cost-effective, enhancing safety in industries handling volatile acids.

Implementation Method 1

a gas-sensitive coating for such volatile acids... shows significant and long-lasting color changes within a short time in case of leakage

Methodology Applied
Scientific EffectColor change: Photochromism

Data Source

PatentEP3831835B1An environment-friendly gas-sensitive coating for volatile acids and the preparation method thereof
Publication Date: 2026.05.06 SHANDONG UNIV
  • EP3831835B1 patent drawingFigure 1~2
  • EP3831835B1 patent drawingFigure 3~4
  • EP3831835B1 patent drawingFigure 5~6

AI summary

The invention relates to an environment-friendly air-sensitive coating for volatile acids and the preparation method thereof, which comprises components in parts by mass as follows: 50-100 parts of strong acid resistant resin, 1-30 parts of special color-changing agent A, 0.5-5 parts of auxiliary color-changing component, 0- 20 parts of fillers, 0-20 parts of auxiliaries and 0-300 parts of solvent. The said special color-changing agent A is a substance obtained by treating the white carbon black with the compound B. The invention is to realize the preparation of the gas-sensitive coating for volatile acids through enhancing the special color-changing agent A's color changing properties in the presence of acid gases with the auxiliary color-changing component and combined with its reasonable compatibility with the pigments, fillers and auxiliaries, etc. The invention has a variety of characteristics, such as obvious in color changing, quick in color changing, reversible in color changing and good compatibility, and is applicable to the surfaces of all units for manufacturing, storage, transportation and use of strong acids. It also has good market prospects in the manufacturing industries, such as petroleum alkylation, fluorine chemical industry, ore flotation, pulp and papermaking industry and semiconductor industry.