Reactive Diluent Combination for Low VOC Alkyd Coatings
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Solution Overview
Problem
Alkyd resin-based coating compositions rely heavily on VOC solvents, which are harmful to health and the environment, and replacing them with alternatives often compromises film properties or increases complexity in the drying process.
Innovation Solution
A combination of reactive diluents comprising a polyester derived from a polyol and a fatty acid or fatty acid methyl ester, along with an unsaturated dibasic acid ester, is used to reduce VOC content while maintaining film properties, with a ratio of 70:30 to 99:1, allowing for low viscosity and efficient incorporation into the polymerized film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If VOC solvents are used to spread the composition on the substrate, then the coating composition achieves good applicability and spreading, but harmful emissions to health and environment increase
Solution Approach 1:
The patent changes the chemical composition parameters by replacing VOC solvents with reactive diluents having different molecular structures and reactivity characteristics. The reactive diluents (glycol esters of dicarboxylic acids) have parameters tailored to provide similar spreading properties while enabling incorporation into the polymerized film, thus reducing harmful emissions while maintaining applicability.
2Object-affected harmful factors
If reactive diluents are used to replace VOC solvents, then VOC emissions are reduced, but the properties of the coating composition are reduced due to small molecules in the polymerized film
Solution Approach 1:
The patent applies local quality by selecting reactive diluents with specific molecular characteristics (glycol esters of dicarboxylic acids) that have appropriate size and reactivity. These diluents are incorporated locally into the polymerized film structure at controlled levels, providing the benefit of reduced VOC emissions while minimizing the negative impact on film properties through careful molecular selection.
Solution Approach 2:
The patent creates a composite system by combining reactive diluents (glycol esters of dicarboxylic acids) with alkyd resin and drying oils. This composite approach allows the reactive diluent to be integrated into the polymerized film matrix, achieving a synergistic effect where the diluent provides low viscosity and reduced VOC emissions while the resin system maintains film integrity and properties.
3Quantity of substance
If the oil length of the resin is increased to reduce solvent need, then fewer VOC solvents are required, but the resin becomes less viscous and the drying process becomes more complex
Solution Approach 1:
The patent extracts the solvent function from the resin system by introducing reactive diluents as separate components. Instead of relying on high oil length resins to reduce viscosity, the invention separates the viscosity-modifying function (performed by reactive diluents) from the resin structure, allowing the resin to maintain optimal oil length for simple drying while the reactive diluent provides the necessary fluidity.
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 achieves a balance of low VOC emissions and high film hardness, with reduced drying time without significant compromise on film properties, making it suitable for various substrates and applications.
Implementation Method 1
the resin molecules bond to each other, this reaction being initiated by contact with oxygen from the air
Implementation Method 2
Reactive diluents are also characterized by their low viscosity, which allows reducing the viscosity of the coating compositions
Implementation Method 3
a first reactive diluent which is a polyester obtainable by reaction of a polyol with a fatty acid or a fatty acid methyl ester
Data Source
Figure 1
AI summary
The present invention concerns a combination of reactive diluents comprising: - a first reactive diluent which is a polyester obtainable by reaction of a polyol with a fatty acid or a fatty acid methyl ester, and optionally an hydroxy acid, and - a second reactive diluent, which is a unsaturated dibasic acid ester. The present invention also concerns a process for preparing such a combination of reactive diluents, a composition comprising the combination, its preparation process and its use.