Odor-Free Rust Removal Using Non-Sulfur Chelating Agents

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Solution Overview

Problem

Current rust removal products, particularly those using thioglycolic acid, emit a strong, unpleasant odor due to sulfur content, posing challenges in ventilation and respiratory safety during use.

Innovation Solution

A composition comprising a reducing agent, a chelating agent that changes color upon chelation, and a solvent, such as lactic acid, 1,10-phenanthroline, and sodium metasilicate, which reduces iron oxide to a soluble form and binds it, allowing for odor-free rust removal without the need for ventilation or respiratory protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thioglycolic acid is used as the active ingredient, then rust removal effectiveness is improved, but strong unpleasant odor is generated

Engineering Contradiction:
Improverust removal effectivenessVSAvoidstrong unpleasant odor
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the sulfur-containing thioglycolic acid component that causes the unpleasant odor, while retaining the essential rust removal function through alternative non-sulfur-based chelating agents and reducing agents. This separation eliminates the harmful odor source while preserving the beneficial rust removal capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters by substituting sulfur-based compounds with non-sulfur-based alternatives, specifically using chelating agents like EDTA, citric acid, or gluconic acid combined with reducing agents such as ascorbic acid or hydroxylammonium chloride. This parameter change maintains rust removal effectiveness while eliminating the foul odor characteristic of thioglycolic acid.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If sulfur-containing compounds are used for rust removal, then chelation effectiveness is improved, but noxious fumes are produced

Engineering Contradiction:
Improvechelation effectivenessVSAvoidnoxious fumes
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces intermediary non-sulfur-based chelating agents that mediate the binding process between the iron particles and the solution. These intermediaries (such as EDTA, citric acid, or gluconic acid) perform the chelation function previously accomplished by sulfur-containing compounds, but without generating noxious fumes or unpleasant odors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful sulfur-containing chemistry into beneficial non-sulfur-based chemistry. By using reducing agents like ascorbic acid or hydroxylammonium chloride instead of sulfur-based reducing agents, the system achieves effective rust removal while converting the harmful sulfur emissions into harmless byproducts, thus turning a potentially harmful process into a safe one.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively removes rust and metallic particles from surfaces without the foul odor associated with thioglycolic acid-based products, ensuring safer and more pleasant usage while maintaining the effectiveness of rust removal.

Implementation Method 1

thioglycolic acid reduces ferrous iron (Fe3+) to ferric iron (Fe2+)

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

the iron chelating agent binds to the soluble iron species in the solution to form an iron chelate

Methodology Applied
Scientific EffectChelation: Chemical Bonding

Implementation Method 3

at least one chelating agent that changes color upon chelation

Methodology Applied
Scientific EffectColor change upon chelation:

Data Source

PatentUS20250019618A1Iron, rust, and metallic deposit removal product and method of using the same
Publication Date: 2025.01.16 STONER INC

AI summary

A composition for removing iron deposits, rust, or metallic particles from a surface, the composition including: at least one reducing agent; at least one chelating agent that changes color upon chelation; and at least one solvent.