Two-Component Solvent Coating for Hardness Without Isocyanates
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Solution Overview
Problem
Existing two-component solvent-based coating compositions that aim to provide hard, scratch-resistant coatings without isocyanate curing agents face challenges such as toxicity, limited storage stability, and undesired odors, while alkyd-based coatings lack the hardness of isocyanate crosslinked coatings.
Innovation Solution
A two-component solvent-based coating composition comprising an autoxidizable resin with unsaturated fatty acids and a metal-ligand complex as a drying catalyst in one component, and a (meth)acrylate compound with a thiol compound in the other, without cobalt and thiol or (meth)acryloyl functional groups, to form hard, scratch-resistant coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If isocyanate-functional curing agents are used to achieve hard, scratch-resistant coatings, then coating hardness and scratch resistance are improved, but user health safety deteriorates due to toxicity
Solution Approach 1:
The patent removes the harmful isocyanate curing agent from the coating system while maintaining the desired coating properties through an alternative chemistry based on autoxidizable resins and thiol compounds, thereby eliminating toxicity while preserving hardness and scratch resistance
Solution Approach 2:
The patent changes the chemical parameters of the curing system by replacing isocyanate groups with a combination of autoxidizable resin functional groups and thiol compounds, achieving similar crosslinking density and coating performance without the toxic isocyanate component
2Temperature
If polythiol is added to alkyd resin to improve curing at low temperatures, then low-temperature curing is improved, but storage stability deteriorates and sulfide odor is generated
Solution Approach 1:
The patent optimizes the equivalence ratio of SH-functional groups to unsaturated carbon-carbon bonds within a specific range (0.04 to 0.12) to achieve low-temperature curing while maintaining storage stability and minimizing sulfide odor, representing a precise parameter optimization to resolve the contradiction
3Strength
If alkyd resins are blended with acryloyl or methacryloyl compounds to increase hardness, then coating hardness is improved, but storage stability deteriorates due to premature crosslinking
Solution Approach 1:
The patent divides the coating composition into two separate components: Component A containing the autoxidizable resin with unsaturated fatty acids and metal-ligand complex, and Component B containing the (meth)acrylate compound with poly(meth)acryloyl functionality and thiol compound. This segmentation prevents premature crosslinking during storage while enabling hard, scratch-resistant coating formation upon mixing and application
Solution Approach 2:
The patent prepares the reactive components separately in advance (Segmentation into Component A and Component B) and combines them only when needed for application, preventing premature crosslinking reactions during storage while ensuring the components are ready to form the desired hard coating structure upon mixing
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 composition results in very hard, scratch-resistant coatings with short tack-free times and acceptable pot life, free from unpleasant odors and storage instability, while maintaining storage stability of the components.
Implementation Method 1
an autoxidizable resin with unsaturated fatty acids and a metal-ligand complex as drying catalyst
Implementation Method 2
a (meth)acrylate compound with poly(meth)acryloyl functionality and a thiol compound
Data Source
AI summary
A two-component solvent-based coating composition comprising a component A comprising an autoxidizable resin comprising unsaturated fatty acids and a metal-ligand complex as drying catalyst, wherein the metal is manganese, vanadium or iron; and a component B comprising a (meth)acrylate compound and a thiol compound, wherein the (meth)acrylate compound is a poly (meth)acryloyl functional ester of (meth)acrylic acid and a polyhydric alcohol or a poly (meth)acryloyl functional dimer of such ester, wherein component B is free of drying catalyst, wherein component A is free of a compound comprising a thiol group and of a compound comprising a (meth)acryloyl functional group, and wherein the coating composition is free of cobalt.