VOC-Free Silane Coating for Metal Corrosion Control

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Solution Overview

Problem

Existing aqueous silane systems for corrosion control are limited by high organic solvent content, VOC emissions, and inability to achieve active corrosion control, while also being unsuitable for industrial-scale processing and repaintability.

Innovation Solution

Development of a virtually VOC-free anti-corrosion composition based on bis-aminosilane cocondensates as binders, compatible with particulate additions, curing at room temperature, and allowing effective adhesion and corrosion control on metal substrates with the option for further coating applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If aqueous silane systems are prepared by mixing silanes with water, then VOC emissions are reduced, but the systems become unstable due to hydrolysis and condensation reactions

Engineering Contradiction:
ImproveVOC emissionsVSAvoidstability of aqueous silane system
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces organic solvents as intermediaries to mediate between the silane components and water. The organic solvents facilitate the dissolution of hydrophobic silanes while controlling the hydrolysis and condensation reactions, thereby maintaining system stability. The solvents act as a bridge that allows aqueous formulation without immediate destabilization.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the composition parameters by carefully controlling the ratios of water, organic solvents, and silane components. By adjusting these parameters and adding specific additives, the system achieves a stable equilibrium that prevents uncontrolled hydrolysis while maintaining low VOC emissions through the aqueous phase.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If silane systems contain organic solvents, then stability is improved, but VOC emissions increase and flash point decreases

Engineering Contradiction:
Improvestability of silane systemVSAvoidVOC emissions
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent creates a multi-phase system where different regions have different compositions. The organic solvents and water form separate phases with distinct functions: the organic phase stabilizes the silane components while the aqueous phase reduces VOC emissions. This local differentiation allows the system to achieve stability without uniform VOC content throughout.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If existing aqueous silane formulations are used, then eco-friendliness is improved, but active corrosion control capability is insufficient

Engineering Contradiction:
Improveeco-friendlinessVSAvoidcorrosion control effectiveness
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent creates a composite silane system combining multiple silane components with different functionalities. The composition includes hydrophobic silanes for water repellency, aminosilanes for corrosion inhibition, and crosslinking agents for adhesion. This composite approach enables the eco-friendly aqueous formulation to achieve active corrosion control through the synergistic interaction of different silane species.

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 solution provides a stable, eco-friendly, and industrially viable anti-corrosion coating that effectively controls corrosion on metal surfaces, allowing for thin film application and good adhesion with organic coatings, while being suitable for various film thicknesses and ensuring effective adhesion and repaintability.

Implementation Method 1

many silanes are insoluble in the aqueous phase and undergo hydrolysis and condensation on contact with water

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

many silanes are insoluble in the aqueous phase and undergo hydrolysis and condensation on contact with water

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

curing at room temperature, and allowing effective adhesion and corrosion control on metal substrates

Methodology Applied
Scientific EffectCuring:

Implementation Method 4

allowing effective adhesion and corrosion control on metal substrates with the option for further coating applications

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11168221B2Aqueous corrosion protection formulation based on silanes
Publication Date: 2021.11.09 EVONIK OPERATIONS GMBH

AI summary

The present invention relates to a composition comprising —a specific binder containing at least one cocondensate based on at least one ω-glycidyloxyalkylalkoxysilane and a bis(alkoxyalkylsilyl)amine, —water, —alcohol in an amount of less than 3% by weight, based on the composition, —at least one addition selected from the group consisting of particulate metals, metal alloys and metal compounds and —optionally at least one additive, where the pH of the composition is from 1 to 14 and the dry residue of the binder is from 1 to 50% by weight, based on the binder used, a process for the production thereof and also the use thereof for coatings, in particular for the protection of metals against corrosion.