Bispidon-Based Chelant Catalysts for Cobalt-Free Alkyd Curing
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Solution Overview
Problem
There is a need for alternative oxidatively curable coating formulations that exhibit acceptable curing rates, as existing alternatives to cobalt-based driers are limited and cobalt soaps are considered carcinogenic, necessitating the development of faster curing agents for alkyd-based resin coatings.
Innovation Solution
Transition metal complexes comprising bispidon ligands with heteroaryl groups other than 2-pyridyl, such as thiazol-2-yl, pyrazin-2-yl, and quinolin-2-yl, are used to catalyze the curing of oxidatively curable alkyd-based resin formulations, accelerating the curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cobalt-based driers are used to accelerate curing of alkyd-based resin formulations, then curing rate is improved, but harmful effects arise due to carcinogenicity of cobalt soaps
Solution Approach 1:
The patent changes the chemical composition parameters by replacing cobalt-based driers with alternative metal complexes (manganese, iron, zinc) that have different health safety profiles while maintaining catalytic activity for curing. This substitution resolves the contradiction by eliminating carcinogenic effects while preserving the desired curing rate enhancement.
Solution Approach 2:
The patent employs alternative metal complexes that can be easily replaced and are less harmful to health and environment. These alternative driers serve as temporary, safer substitutes during the curing process, eliminating the need for persistent cobalt-based compounds in the final coating formulation.
2Object-affected harmful factors
If alternative metal complexes (manganese, iron, zinc) are used to replace cobalt driers, then harmful effects are reduced, but curing rate may be insufficient
Solution Approach 1:
The patent creates composite metal complex structures by combining alternative metals (manganese, iron, zinc) with specific organic ligands and auxiliary driers to achieve both safety and effective curing performance. This composite approach allows the benefits of safer metals to be combined with catalytic efficiency through synergistic interactions between multiple components.
Solution Approach 2:
The patent introduces auxiliary driers and organic ligands as intermediary substances that enhance the catalytic activity of alternative metal complexes. These intermediaries facilitate more efficient curing by mediating between the safer alternative metals and the alkyd resin, compensating for any inherent lower activity of the alternative metals compared to cobalt.
3Productivity
If bispidon-based chelants with heteroaryl groups are used, then curing is accelerated, but formulation complexity increases
Solution Approach 1:
The patent segments the drier system into separate functional components: the bispidon-based chelant that provides catalytic activity and the auxiliary driers that enhance performance. This segmentation allows each component to be optimized independently and simplifies the overall formulation process by breaking down the complex catalysis system into manageable parts that can be selected and combined based on specific application requirements.
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
These complexes catalyze faster curing of oxidatively curable coating formulations, outperforming expectations based on their structural similarity with analogous bis(2-pyridyl) bispidon complexes, thereby addressing the need for efficient and cobalt-free drying processes.
Implementation Method 1
unsaturated groups, in particular carbon-carbon double bonds, can react with oxygen from the air, causing the oils to crosslink, forming a three-dimensional network, and harden
Implementation Method 2
small, i.e. catalytic, quantities of optionally organic metal salts, often referred to as metal driers, which catalyse the polymerisation of unsaturated material
Implementation Method 3
Redox-active metals, such as iron, manganese, cobalt, vanadium and copper enhance radical formation, and thus the oxidative curing process
Data Source
AI summary
The present invention relates to an oxidatively curable coating formulation comprising an oxidatively curable alkyd-based resin and a bispidon-based chelant, which chelant may optionally be complexed with a suitable transition metal ion. The formulations may be paints or other oxidatively curable coating compositions. The invention also provides methods for making such formulations and compositions resultant from the curing of such formulations.