Polyaspartate Coating Segmentation for Metal Adhesion
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Solution Overview
Problem
Cured coatings based on polyaspartic-acid-containing compositions exhibit poor adhesion to critical metallic surfaces, inadequate gloss retention when exposed to weathering, and insufficient water resistance.
Innovation Solution
A layer structure comprising a partially or fully cured coating composition for a pigmented coating (BP) and a clearcoat (BK), where BP includes polyaspartic esters, silane-functional polyisocyanates, and pigments, and BK includes polyaspartic esters and polyisocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If polyaspartic-acid-containing coating compositions are used, then rapid curing at low temperatures is achieved, but adhesion to metallic surfaces deteriorates
Solution Approach 1:
The coating system is divided into two separate layers: a primer layer (BP) containing polyaspartic esters and silane-functional polyisocyanates for rapid curing and adhesion, and a clearcoat layer (BK) containing polyaspartic esters and polyisocyanates for weathering resistance. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The patent employs composite material formulations in both layers. The primer combines polyaspartic esters with silane-functional polyisocyanates to create a material that simultaneously achieves rapid curing, adhesion to metal, and water resistance. The clearcoat combines polyaspartic esters with polyisocyanates for gloss retention and weathering resistance.
2Use of energy by moving object
If silane-modified polyisocyanates with allophanate groups are used, then adhesion to metallic surfaces is improved, but gloss retention when exposed to weathering deteriorates
Solution Approach 1:
The patent separates the adhesion function (primer layer with silane-modified polyisocyanates) from the weathering resistance function (clearcoat layer with polyisocyanates). This segmentation allows the primer to provide strong metal adhesion while the clearcoat protects the underlying layer and maintains gloss under weathering conditions.
Solution Approach 2:
The solution moves from a single-layer system to a two-layer vertical structure, adding the dimension of layering. The primer layer addresses adhesion to the substrate, while the clearcoat layer addresses exposure to weathering, allowing both requirements to be satisfied simultaneously in different spatial zones.
3Reliability
If polyaspartic-ester-containing coating compositions are used, then water resistance is improved, but adhesion to critical metallic surfaces deteriorates
Solution Approach 1:
The coating system is segmented into a primer layer that provides adhesion to metal surfaces and a clearcoat layer that provides water resistance. The primer contains polyaspartic esters combined with silane-functional polyisocyanates for optimal adhesion, while the clearcoat contains polyaspartic esters with polyisocyanates for enhanced water resistance and weathering protection.
Solution Approach 2:
The patent merges the functions of adhesion and water resistance into a coordinated two-layer system where the primer and clearcoat work together. The silane-functional polyisocyanates in the primer provide both adhesion to metal and contribute to water resistance, while the clearcoat reinforces the water resistance property.
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 layer structure achieves good adhesion to metallic surfaces, maintains gloss retention under weathering, and provides high water resistance.
Implementation Method 1
at least one silane-functional polyisocyanate containing at least one silane group of the general formula (III)
Implementation Method 2
coating composition BP comprises at least one polyaspartic-ester-containing component, at least one silane-functional polyisocyanate
Implementation Method 3
secondary polyamines containing ester groups have become established in recent years that, in combination with paint polyisocyanates, are particularly suitable as binders in low-solvent or solvent-free (high-solids) coating compositions and allow rapid curing of the coatings at low temperatures
Data Source
AI summary
The invention relates to a layer construction comprising at least one coating composition, which is partially or completely hardened, for a pigmented lacquer (Bp) and at least one coating composition, which is applied thereon, for a clear lacquer (BK), wherein the coating composition Bp contains at least one polyaspartic acid-containing component, at least one silane-functional polyisocyanate, and at least one pigment, and the coating composition BK likewise contains at least one polyaspartic acid-containing component and at least one polyisocyanate. The invention also relates to a layer system comprising a substrate, at least one coating composition Bp, which is applied onto at least one section of the substrate and is partly or completely cured, and at least one coating composition BK, which is applied thereon. The invention also relates to a method for producing a cured layer construction on a preferably metal substrate and to a layer system comprising a preferably metal substrate and a layer construction which can be obtained according to the aforementioned production method.