Metal Substrate Pretreatment for Flash Rust-Free Coating
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Solution Overview
Problem
Existing rust inhibiting formulations for metallic substrates contain harmful compounds like nitrogen and phosphorous, which negatively impact health and the environment, and are not effective in preventing flash rust formation during or after cleaning and rinsing processes, interfering with subsequent coating steps.
Innovation Solution
A method involving cleaning, chemical pre-treatment, and rinsing steps using compositions containing 0.8 to 200 mmol/L of compounds of formula (I), where the COOH group can be fully or partially neutralized, and residues R1, R2, R3, R4, and R5 are independently selected from H or hydroxy and alkyl groups, to prevent flash rust without interfering with subsequent coating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rust inhibiting formulations containing nitrogen and phosphorous compounds are used, then rust formation is inhibited, but health and environmental security are negatively impacted
Solution Approach 1:
The patent changes the chemical composition parameters by replacing nitrogen-containing compounds (nitrites, nitrates) and phosphorous-containing compounds with carboxylic acid compounds (acetic acid, acrylic acid, stearic acid) and their salts. This substitution maintains the rust inhibition function while eliminating the harmful health and environmental effects associated with traditional inhibitors.
Solution Approach 2:
The patent employs temporary anticorrosive oils and carboxylic acid-based rinsing compositions that can be easily applied and rinsed off, replacing persistent harmful substances. These compositions provide adequate protection during the critical pre-treatment phase and do not remain as harmful residues on the metallic substrate.
2Reliability
If nitrogen-containing rust inhibitors like sodium nitrite are used, then flash rust formation is prevented, but toxic nitrite ions are released affecting health and environment
Solution Approach 1:
The patent converts the harmful effect of nitrite ions into a beneficial approach by using carboxylic acid compounds that provide rust inhibition through a different mechanism. The acetic acid, acrylic acid, and stearic acid-based compositions prevent flash rust formation without releasing toxic ions, turning a harmful substance into a safe alternative.
3Reliability
If phosphorous containing rust inhibitors are used, then corrosion protection is enhanced, but environmental issues arise
Solution Approach 1:
The patent changes the chemical composition by eliminating phosphorous-containing compounds and replacing them with carboxylic acid-based compositions. This substitution maintains corrosion protection capabilities while resolving the environmental issues associated with phosphorous inhibitors, particularly in the context of rinsing compositions that must be environmentally friendly.
4Manufacturing precision
If cleaning compositions are used to remove impurities from metallic substrates, then surface cleanliness is improved, but rust formation occurs during or after rinsing
Solution Approach 1:
The patent applies a temporary anticorrosive oil composition to the cleaned metallic substrate before rinsing, and uses carboxylic acid-based rinsing compositions that contain rust inhibitors. This preliminary protective action prevents rust formation during the critical period when the surface is most vulnerable after cleaning, bridging the gap between cleaning and final coating application.
Solution Approach 2:
The patent introduces temporary anticorrosive oils and carboxylic acid-based rinsing compositions as intermediary substances between the cleaning step and the final coating application. These intermediaries provide rust protection during the vulnerable period when the metallic surface is exposed after cleaning, preventing rust formation without interfering with subsequent coating steps.
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 method effectively inhibits flash rust formation on metallic substrates, ensuring compatibility with subsequent coating steps and reducing environmental and health risks associated with traditional rust inhibitors.
Implementation Method 1
the method effectively inhibits flash rust formation on metallic substrates
Data Source
AI summary
Disclosed herein is a method of pre-treating a metallic substrate, the method including one or more cleaning steps, where at least part of the surface of the metallic substrate is contacted with one or more aqueous cleaning compositions, to obtain a cleaned metallic substrate; and/or one or more chemical pre-treatment steps selected from the group consisting of conversion treating steps, passivation treating steps and thin-layer forming steps, where at least part of the surface of a metallic substrate is contacted with one or more chemical pre-treatment compositions selected from the group consisting of conversion treatment compositions, passivation treatment compositions and thin-layer forming compositions to obtain a chemically pre-treated substrate. Also disclosed herein is a method of coating a metallic substrate, where the first step consists of the method of pre-treating a substrate, where after a last rinsing step one or more coating compositions are applied and cured.