High Molecular Weight Dian Epoxy Resin Colour Stability
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Solution Overview
Problem
High molecular weight dian epoxy resins used in powder hybrid paints tend to discolour during curing, especially at elevated temperatures, leading to colour instability and loss of intended colour, which is challenging to address with existing methods that require expensive micronized additives and limit the use of liquid antioxidants.
Innovation Solution
A method for modifying high molecular weight dian epoxy resins by incorporating a combination of phenolic and phosphite antioxidants during the synthesis process under specific temperature and oxygen-free conditions, using a phase-transfer catalyst, to prevent oxidation and colour changes during curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight dian epoxy resin is used in powder hybrid paints, then the resin provides good film properties and curing performance, but the resin tends to discolour during curing especially at elevated temperatures
Solution Approach 1:
Antioxidants are incorporated into the epoxy resin during the synthesis process before the resin is used in paint formulations. This preliminary incorporation ensures the antioxidants are already present and distributed throughout the resin matrix, providing protection against discolouration during subsequent curing and storage without requiring additional additives in the paint composition.
Solution Approach 2:
The patent modifies the chemical composition of the epoxy resin by incorporating antioxidants (such as phenolic antioxidants like BHT or phosphite antioxidants) during synthesis. This changes the resin's chemical parameters to include antioxidant functionality, which prevents oxidation and discolouration while maintaining the resin's curing performance and film-forming properties.
2Object-affected harmful factors
If antioxidants are added at the stage of initial milling to prevent discolouration, then colour stability is improved, but expensive micronized additives must be used and liquid antioxidants cannot be used
Solution Approach 1:
Instead of adding antioxidants during the paint formulation stage (initial milling), the antioxidants are incorporated into the epoxy resin itself during its synthesis. This eliminates the need for separate antioxidant addition steps in paint manufacturing and allows the use of standard liquid or solid antioxidants without requiring expensive micronization processes.
Solution Approach 2:
The patent combines the epoxy resin synthesis process with antioxidant incorporation into a single integrated process. The antioxidants are added to the epoxy resin during its polycondensation or polyaddition reaction, merging two separate operations (resin synthesis and antioxidant incorporation) into one, thereby simplifying manufacturing and reducing costs.
3Object-affected harmful factors
If the concentration of antioxidants in the paint composition is increased to improve colour stability, then discolouration resistance is improved, but the complexity of paint formulation and application increases
Solution Approach 1:
The antioxidant functionality is merged into the epoxy resin molecule itself through incorporation during synthesis. This means the resin already contains the necessary antioxidant concentration built-in, eliminating the need for separate antioxidant additives in the paint formulation and simplifying the overall paint composition without compromising discolouration resistance.
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 method achieves significant colour stability and resistance against discolouration, maintaining the intended colour throughout the synthesis and curing process, even at elevated temperatures, without the need for additional antioxidants in the paint composition.
Implementation Method 1
The side reactions are unwanted and affect adversely the final product properties... The manufacturers of saturated polyester resins intended for powder paints, in order to obtain the final product having the desired colour, use antioxidants that prevent discolouration of the polyester in the course of the synthesis.
Implementation Method 2
A method for modifying high molecular weight dian epoxy resins by incorporating a combination of phenolic and phosphite antioxidants during the synthesis process under specific temperature and oxygen-free conditions, using a phase-transfer catalyst
Data Source
AI summary
The invention concerns a method for manufacturing of a high molecular weight dian epoxy resin having epoxide equivalent of 714 - 833, being modified with a phenolic and a phosphite antioxidants, in the course of synthesis from a low molecular weight epoxy resin having epoxide equivalent of 0.440 - 0.510 mol/100 g and bisphenol A, by a polyaddition method under an oxygen-free atmosphere, in the presence of a phase-transfer catalyst.