Polyester Polyol Primer for Chip Resistance
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Solution Overview
Problem
Current coating compositions for automotive refinish processes are time-consuming and expensive due to labor and volatile organic abatement engineering requirements, and they lack sufficient chip resistance and intercoat adhesion, necessitating a more efficient and effective solution for protecting vehicle bodies from chipping and corrosion.
Innovation Solution
A coating composition comprising a polyester with at least two reactive hydroxyl groups, a material with functional groups reactive with the polyester, and a free acid, which forms a multi-layer coating system that enhances chip resistance and intercoat adhesion, allowing for simplified refinishing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional multi-layer coating systems are used to achieve chip resistance and corrosion protection, then protective properties are improved, but the number of coating layers and process complexity increase
Solution Approach 1:
The patent combines multiple functions (corrosion protection, chip resistance, adhesion promotion) into a single primer coating layer. This is achieved by formulating the primer with specific polyester resins, epoxy resins, and corrosion-inhibiting pigments that work together to provide comprehensive protection, eliminating the need for separate undercoat and surfacer layers while maintaining or improving protective properties
Solution Approach 2:
The primer coating is designed to perform multiple functions simultaneously: it provides corrosion inhibition through pigments like zinc phosphate, achieves chip resistance through proper resin formulation and film build, and ensures adhesion to both metal substrates and topcoats. This multi-functional design allows a single layer to replace traditional multi-layer systems
2Reliability
If traditional refinish processes with multiple undercoats are applied, then adequate protection is achieved, but labor time and costs increase
Solution Approach 1:
The primer coating is formulated to provide preliminary corrosion protection and surface preparation in a single application. By incorporating corrosion-inhibiting pigments and adhesion promoters directly into the primer, the system performs preliminary protective actions that would traditionally require multiple subsequent layers, thereby reducing overall process time while maintaining protection levels
3Reliability
If corrosion inhibitive pigments are added to primer compositions, then corrosion resistance is improved, but intercoat adhesion may be compromised
Solution Approach 1:
The patent uses different types of pigments with specific local functions: corrosion-inhibiting pigments (zinc phosphate, strontium chromate) provide localized corrosion protection at the metal-coating interface, while separate adhesion promoters and resin systems ensure broad-spectrum intercoat adhesion. This spatial and functional differentiation allows both requirements to be met simultaneously without compromise
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 described coating composition improves chip resistance and intercoat adhesion, reducing the need for multiple undercoats and simplifying the refinishing process, thereby decreasing costs and time while providing effective protection against chipping and corrosion.
Implementation Method 1
a polyester comprising at least two reactive hydroxyl groups and comprising the reaction product of reactants comprising (i) a polycarboxylic acid comprising more than two acid groups per molecule and (ii) a hydroxyl-containing compound comprising no more than two hydroxyl groups per molecule; (b) a material comprising at least two functional groups reactive with the hydroxyl groups of the polyester
Implementation Method 2
curing the composition
Data Source
AI summary
Coating compositions are disclosed comprising a polyester comprising at least two reactive hydroxyl groups, a material comprising at least two functional groups reactive with the hydroxyl groups of the polyester, and a free acid. Methods of using the coatings, methods for refinishing an article with the coatings, and the substrates coated therewith, are also disclosed.