Metallic Surface Treatment with Stabilized Linear Polymers
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Solution Overview
Problem
Metallic surfaces, particularly steel and galvanized steel, face issues with corrosive sub-surface migration and polymer precipitation during treatment with acidic aqueous compositions, leading to destabilization and reduced corrosion resistance and stone chip resistance.
Innovation Solution
A method involving a two-step treatment process using an acidic aqueous composition containing metal compounds and hydrolysable organosilane compounds, followed by a second composition with linear polymers prepared by controlled radical polymerization, specifically comprising N,N-dimethyl (meth)acryl amide and vinylphosphonic acid monomeric units, to prevent polymer precipitation and enhance corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acidic aqueous compositions containing polymers are used to treat metallic surfaces, then corrosion protection and adhesion are improved, but polymer precipitation occurs causing filter clogging and bath depletion
Solution Approach 1:
The patent changes the chemical parameters of the aqueous composition by introducing a specific polymer stabilizer compound that prevents polymer precipitation. This stabilizer compound modifies the solution chemistry to maintain polymer solubility while preserving the corrosion protection benefits, thereby eliminating filter clogging and bath depletion issues.
Solution Approach 2:
The patent employs a polymer stabilizer compound as an intermediary substance that mediates between the polymer and the acidic aqueous environment. This stabilizer compound prevents direct interaction between the polymer and conditions that would cause precipitation, allowing the polymer to remain dissolved and functional without causing harmful effects.
2Reliability
If polymers are added to acidic aqueous compositions to improve corrosion resistance, then sub-surface migration is reduced, but stone chip resistance may be detrimentally affected
Solution Approach 1:
The patent optimizes the chemical parameters by selecting specific polymer stabilizer compounds and controlling their concentration levels. This parameter optimization allows the polymer to provide corrosion resistance through sub-surface migration prevention while maintaining stone chip resistance by preventing excessive polymer aggregation that would compromise coating integrity.
Solution Approach 2:
The patent applies local quality by ensuring the polymer stabilizer is distributed uniformly throughout the aqueous composition, creating localized stable polymer chains that provide corrosion protection at the metal surface without forming aggregates that would reduce stone chip resistance. The stabilizer compound ensures uniform polymer distribution and prevents localized precipitation.
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 significantly reduces sub-surface migration and enhances corrosion resistance under severe test conditions, while maintaining or improving stone chip resistance, as demonstrated by accelerated corrosion tests.
Implementation Method 1
hydrolysable organosilane compounds (S) or their hydrolysis products (HS) and/or condensation products (CS)
Implementation Method 2
The coatings formed from these compositions provide a certain corrosion protection and adhesion to subsequent coating layers
Implementation Method 3
the polymer does not tend to precipitate and stays in a solubilized form
Implementation Method 4
the treated metallic surface shows an enhanced corrosion resistance even under severe test conditions as e.g. the accelerated corrosion test according to PV1210 (20 cycles) or the ACT I test. Particularly less sub-surface migration should be observed
Data Source
AI summary
Described herein is a method for treatment of a metallic surface, including the step of (A) contacting the metallic surface with a first aqueous composition, and a subsequent step of (B) contacting the metallic surface subsequent to step (A) with a second aqueous composition. Also described herein is a kit-of-parts including the first and second aqueous composition and a kit-of-parts including master-batches of the first and second aqueous compostions. Also described is a method of using the kit-of-parts for treating a metallic surface and substrates including the thus treated metallic surfaces.