Unsaturated Polyester Resin Process Reducing Fumaric Acid
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Solution Overview
Problem
Existing processes for producing unsaturated polyester resins for toners result in high levels of particle fines, which hinder toner performance and lead to poor imaging quality due to unreacted fumaric acid in the resin.
Innovation Solution
A process involving reacting an organic diol with a cyclic alkylene carbonate in the presence of a catalyst to form a polyalkoxy diol, followed by an esterification reaction with diacid reagents and subsequent polycondensation with an unsaturated diacid to produce an unsaturated polyester resin with reduced unreacted starting materials, optimizing the resin formulation and process to minimize particle fines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polycondensation process is used to produce unsaturated polyester resin, then resin can be manufactured with standard properties, but high levels of particle fines are generated due to unreacted fumaric acid
Solution Approach 1:
The patent applies preliminary action by adding fumaric acid after the main polycondensation reaction has progressed to high conversion (90-95%), rather than at the beginning. This timing allows the resin to first achieve high molecular weight and low viscosity, then incorporates fumaric acid to provide unsaturation for crosslinking without causing excessive particle fines, as the reaction conditions are already optimized at this stage
Solution Approach 2:
The patent changes key process parameters including: (1) adding fumaric acid at high conversion levels (90-95%) rather than at the start, (2) maintaining specific temperature ranges (180-220°C) during fumaric acid incorporation, (3) controlling catalyst levels (0.01-1% metal catalysts like tin or titanium compounds), and (4) adjusting monomer ratios to achieve optimal balance between reaction completeness and particle fine generation
2Strength
If fumaric acid is incorporated into the resin, then crosslinking capability and gel content are improved, but unreacted fumaric acid remains and causes particle fines
Solution Approach 1:
The patent performs preliminary polycondensation to high conversion (90-95%) before adding fumaric acid. This ensures the resin achieves high molecular weight and low viscosity first, creating an optimized matrix that can incorporate fumaric acid effectively for crosslinking without leaving excessive unreacted material that would cause particle fines
Solution Approach 2:
The patent maintains continuous heating and stirring during the fumaric acid incorporation stage, ensuring complete reaction and minimizing unreacted fumaric acid. The process continues until acid value reaches target levels (15-40 mg KOH/g), ensuring thorough incorporation of fumaric acid into the polymer matrix for effective crosslinking
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 optimized process significantly reduces unreacted fumaric acid levels, resulting in toners with fewer particle fines and improved machine performance, leading to enhanced imaging quality.
Implementation Method 1
reacting an organic diol with a cyclic alkylene carbonate in the presence of a catalyst to thereby form a polyalkoxy diol
Implementation Method 2
reacting the polyalkoxy diol with one or more diacid reagents in the presence of a second catalyst in an esterification reaction
Implementation Method 3
subsequently polycondensing the resulting mixture with an unsaturated diacid to form an unsaturated polyester resin
Data Source
AI summary
Unsaturated polyester resins and processes for making the same are disclosed herein. In particular, the process for making the resin provides resins with improved properties. The unsaturated polyester resins have substantially reduced free fumaric acid as compared to that made from conventional processes. The toner resins are used to prepare toner compositions that have improved performance.