Unsaturated Polyester Resin Process for Toner Fusing
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Solution Overview
Problem
Current methods for producing polyester resins for toner compositions are not optimized for cost-effectiveness and simplicity, and there is a need for improved processes to achieve desired properties such as low fixing temperatures and high offset properties in electrophotographic toners.
Innovation Solution
A multistep 'one pot' process involving the alkoxylation of a diol with a cyclic alkylene carbonate, followed by the addition of a diacid or anhydride, which allows for the formation of unsaturated polyester resins with controlled isomer composition and molecular weight, enabling the production of toners with specific glass transition temperatures and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polycondensation process is used to prepare polyester resins, then the process is well-established and produces acceptable results, but the process is not optimized for cost-effectiveness and simplicity
Solution Approach 1:
The patent combines the alkoxylation step and polycondensation step into a single integrated process. The diol is first alkoxylated with cyclic alkylene carbonate in the presence of a catalyst, and then the diacid or anhydride is added to the same reaction mixture for polycondensation, eliminating the need for separate preparation and purification steps
Solution Approach 2:
The reaction vessel serves multiple functions: it acts as the reaction container for alkoxylation, the mixing vessel for adding diacid/anhydride, and the polycondensation reactor all in sequence. This multi-functional approach simplifies the manufacturing process and reduces equipment requirements
2Manufacturing precision
If unsaturated polyester resins are prepared with controlled isomer composition, then the glass transition temperature and toner properties are optimized, but the process complexity increases
Solution Approach 1:
The patent controls isomer composition by carefully selecting and controlling reaction parameters including temperature (160-200°C for alkoxylation, 180-220°C for polycondensation), catalyst type and amount, reactant ratios, and reaction time. These parameter changes enable precise control over the resulting polyester's molecular structure and properties without adding complex equipment
3Temperature
If polyester resins are crosslinked to achieve high glass transition temperatures, then toner blocking is reduced, but the minimum fusing temperature increases
Solution Approach 1:
The patent optimizes the balance between glass transition temperature and fusing temperature by controlling the degree of crosslinking through catalyst selection and reaction conditions. By adjusting catalyst type and amount, as well as reaction temperature and time, the process achieves high glass transition temperature for blocking prevention while maintaining adequate fusing properties for electrophotographic application
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 process results in unsaturated polyester resins that can be crosslinked to achieve high glass transition temperatures for reduced toner blocking and low minimum fusing temperatures, enhancing the performance and energy efficiency of electrophotographic devices.
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
subsequently polycondensing the resulting mixture with an unsaturated diacid and/or an anhydride
Implementation Method 3
The process results in unsaturated polyester resins that can be crosslinked to achieve high glass transition temperatures
Data Source
AI summary
The present disclosure provides processes for the preparation of unsaturated polyesters. In embodiments, a process of the present disclosure includes reacting an organic diol with a cyclic alkylene carbonate in the presence of a first catalyst to thereby form a polyalkoxy diol, optionally adding thereto a further amount of cyclic alkylene carbonate in the presence of a second catalyst, and subsequently polycondensing the resulting mixture with a dicarboxylic acid in combination with an anhydride.