Painted Flat Metal Coating with Dual Curing for Adhesion

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Solution Overview

Problem

Existing coil coating processes face challenges in decarbonization, energy efficiency, and minimizing paint delamination/flaking, particularly with the introduction of solvent-free, radiation-curing coating materials, which pose risks to product quality and adhesion.

Innovation Solution

A method involving thermal curing using porous gas burners for base coatings and actinic radiation for top coatings, utilizing complementary reactive functional groups and energy-efficient solvent recovery, combined with solvent-free or low-VOC topcoats, to achieve resource savings and minimize delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If solvent-free, radiation-curing coating materials are used to decarbonize and reduce energy consumption, then energy efficiency and VOC emissions are improved, but adhesion and product quality deteriorate due to embrittlement and delamination risks

Engineering Contradiction:

Improveenergy consumptionVSAvoidadhesion

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The coating system is segmented into multiple functional layers: a primer layer applied first that provides adhesion to the metal substrate, followed by a radiation-curing topcoat layer that provides the protective and aesthetic functions. This segmentation allows each layer to be optimized for its specific function, with the primer ensuring adhesion and the topcoat providing UV resistance and gloss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The primer layer acts as an intermediary between the metal substrate and the radiation-curing topcoat. It mediates the adhesion function, ensuring that the topcoat adheres properly to the substrate without requiring the substrate itself to have adhesion properties compatible with radiation-curing materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If radiation-curing topcoats are applied directly to metal substrates, then process steps are reduced and productivity is improved, but adhesion deteriorates due to the narrow process window for cleaning and conversion treatment

Engineering Contradiction:

Improveprocess efficiencyVSAvoidadhesion

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The primer layer is applied in advance as a preliminary action to prepare the substrate surface. This preliminary coating creates a stable base that is compatible with subsequent radiation-curing topcoats, ensuring proper adhesion before the final topcoat application.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If conventional drying ovens are used for thermal crosslinking, then coating curing is achieved, but energy consumption and fossil fuel use increase

Engineering Contradiction:

Improvecoating curingVSAvoidfossil fuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The conventional thermal drying oven system is replaced with a radiation-curing system that uses UV or electron beam radiation to crosslink the coating. This substitution eliminates the need for high-temperature thermal processing and fossil fuel-based heating, dramatically reducing energy consumption and greenhouse gas emissions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The curing mechanism is changed from thermal parameters (high temperature, long duration) to radiative parameters (UV wavelength, electron beam energy). This parameter change enables rapid curing at ambient or elevated temperatures without requiring fossil fuel-based heating systems.

Inventive Principle:

Principle #35Parameter changes

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 reduces energy consumption, minimizes VOC emissions, and enhances adhesion by optimizing crosslinking processes, thereby reducing the risk of paint delamination and promoting decarbonization.

Implementation Method 1

at least partially crosslinking the liquid-applied base coat on the metal flat product by means of thermal radiation with a thermal radiation unit in the form of a porous gas burner

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

at least partially crosslinking the liquid-applied top coat on the metal flat product by means of actinic radiation with a radiation unit

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4711050A1Method for producing a painted flat metal product

Publication Date: 2026.03.18 THYSSENKRUPP STEEL EUROPE AG PATENTE PATENT DEPARTMENT

Figure 1

AI summary

The invention relates to a method for producing a painted metal flat product (6) according to claim 1.