Thiol-Functional Compound for Coating Compatibility and Drying
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Solution Overview
Problem
Thiol-functional compounds with an average functionality of 3 or lower in coating compositions result in insufficient crosslinking and long drying times, and have limited compatibility with other paint system components, particularly binders and crosslinkers, leading to adverse effects and restricted usage.
Innovation Solution
Development of thiol-functional compounds with at least 3.1 thiol groups per molecule, derived from 2-mercapto acetic acid, 2-mercapto propionic acid, or 3-mercapto propionic acid, which are obtained by reacting a thiol-functional precursor compound with an epoxide-functional or acryloyl-functional compound, enhancing compatibility and reducing costs by using readily available mercapto-carboxylic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thiol-functional compounds with functionality of 3 or lower are used in coating compositions, then crosslinking density and drying speed are improved, but compatibility with binders and crosslinkers deteriorates, leading to adverse effects
Solution Approach 1:
The invention changes the chemical structure parameters of thiol-functional compounds by introducing specific alkyl chains and controlling the ratio of thiol groups to other functional groups. This structural modification enables the compound to achieve both high reactivity (for fast drying) and good compatibility with paint system components, resolving the contradiction between drying speed and compatibility
Solution Approach 2:
The invention creates a composite thiol-functional compound that integrates multiple functional groups (thiol, hydroxyl, carboxyl) within a single molecular structure. This composite approach allows the compound to simultaneously perform crosslinking functions and maintain compatibility with various paint components, eliminating the trade-off between reactivity and compatibility
2Loss of time
If thiol-functional compounds with functionality of 3 or lower are used, then drying time is reduced, but crosslinking density becomes insufficient
Solution Approach 1:
The invention optimizes the thiol functionality parameter to be greater than 3 (specifically 3.1 to 4.0), which provides sufficient crosslinking density while maintaining reasonable drying time. This parameter optimization resolves the contradiction between achieving adequate crosslinking and avoiding excessively long drying times
3Quantity of substance
If higher amounts of thiol-functional compounds are included as reactive diluents, then coating composition performance is improved, but compatibility problems and adverse effects increase
Solution Approach 1:
The invention modifies the molecular structure parameters of thiol-functional compounds by incorporating specific alkyl chains and controlling functional group ratios. These structural changes enhance the compound's compatibility with paint system components, allowing higher inclusion levels (up to 50 wt% or more of the total composition) without causing adverse effects such as phase separation or gelation
Solution Approach 2:
The invention designs a composite molecular structure that integrates thiol groups for crosslinking with hydroxyl and carboxyl groups for compatibility. This multi-functional composite structure enables the compound to act as both a reactive diluent and a compatibility enhancer, allowing higher concentrations to be used without compromising system stability
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 improved thiol-functional compounds demonstrate increased compatibility with paint system components, allowing higher inclusion levels without adverse effects, and can be combined with OH-functional acrylic polymers, reducing volatile organic solvents and achieving rapid drying properties in coating compositions.
Implementation Method 1
the compound is obtainable by reaction of a part of the thiol groups of a thiol-functional precursor compound with an epoxide-functional or acryloyl-functional compound
Data Source
AI summary
The invention relates to a thiol-functional organic compound having on average at least 3.1 thiol groups per molecule, and having carbon atoms, oxygen atoms, and sulfur atoms, and optionally further heteroatoms, and wherein the ratio of the number of carbon atoms (C) to the sum of the number of heteroatoms (HA), (C/HA) is at least 2.0,and wherein the thiol groups are derived from 2-mercapto acetic acid, 2-mercapto propionic acid, or 3-mercapto propionic acid, or esters thereof;and to a liquid coating composition comprising the thiol-functional compound and a thiol-reactive crosslinker.