Phosphonic Diester Catalysts for Stable Thermal Curing
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Solution Overview
Problem
Existing thermally curable mixtures comprising polyols, amino resins, and polyisocyanates face issues with stability in storage and short potlife, leading to logistical and technical problems in painting operations, and struggle to incorporate all components into a three-dimensional network effectively.
Innovation Solution
The use of phosphonic diesters and diphosphonic diesters as reactants or catalysts for transesterification, transamidation, and self-condensation reactions, allowing for stable storage and high reactivity during thermal curing, enabling the incorporation of both amino resins and polyisocyanates into a three-dimensional network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alcoholic solutions of acidic phenyl phosphate are used as catalysts for thermal crosslinking, then the crosslinking reaction can be catalyzed, but the stability in storage deteriorates due to high reactivity of polyisocyanates toward alcohols
Solution Approach 1:
The patent introduces phosphonic diesters and diphosphonic diesters as intermediary catalysts that mediate the crosslinking reaction between polyisocyanates and polyols without requiring alcoholic solutions. These phosphonic compounds act as a bridge, enabling catalysis while avoiding the harmful interaction between alcohol and polyisocyanate that plagues conventional systems.
Solution Approach 2:
The invention changes the chemical parameter of the catalyst from alcoholic phenyl phosphate to phosphonic diesters/diphosphonic diesters. This parameter change fundamentally alters the catalyst's interaction with polyisocyanates, eliminating the premature reaction that occurs with alcoholic catalysts while maintaining effective crosslinking catalysis.
2Reliability
If conventional catalysts are used, then crosslinking can occur, but the potlife becomes too short causing logistical and technical problems in painting operations
Solution Approach 1:
The patent changes the chemical nature of the catalyst from traditional alcoholic phenyl phosphate to phosphonic diesters and diphosphonic diesters. This parameter change results in a catalyst that provides sustained reactivity control, extending the potlife from insufficient duration to a practical working timeframe that allows complete painting operations to be finished.
3Reliability
If high imino melamine resins are used to obtain three-dimensional network, then all three building blocks can be incorporated, but the viscosity increases due to high molecular weights
Solution Approach 1:
The patent changes the molecular weight parameter of the melamine resin from high molecular weight (high imino) to low molecular weight variants. This parameter change enables the formation of three-dimensional networks while keeping the viscosity at acceptable levels, allowing all three building blocks (polyol, amino resin, polyisocyanate) to be effectively incorporated without processing difficulties.
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 new thermally curable mixtures exhibit improved stability in storage, extended potlife, and high reactivity during curing, resulting in coatings that are hard, abrasion-resistant, scratch-resistant, and of high gloss and clarity.
Implementation Method 1
The use of phosphonic diesters and diphosphonic diesters as reactants or catalysts for transesterification, transamidation, and self-condensation reactions
Data Source
AI summary
Disclosed herein is a thermally curable mixture, comprising at least one phosphonic diester (A), at least one diphosphonic diester (A), or at least one phosphonic diester and at least one diphosphonic diester (A); and at least one compound (B) which can be reacted by transesterification, transamidation, self-condensation of N-hydroxyalkylamino groups, self-condensation of N-alkoxyalkylamino groups, transacctalization of N-alkoxyalkylamino groups, acctalization of N-hydroxyalkylamino groups, or a combination thereof. Also disclosed is a process for making the thermally curable mixture, and a cured material comprising the product of thermally curing the mixture.