Polyester Toner Hydrolysis Resistance via Succinic Acid
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Solution Overview
Problem
Toner production using polyesters as resin binders faces challenges in controlling particle size during pulverization and suffers from hydrolysis of ester bonds in aqueous processes, leading to deteriorated storage stability and fixing properties.
Innovation Solution
A polyester is produced by polycondensing an alcohol component with a carboxylic acid component containing structural isomers of alkyl succinic acid and alkenyl succinic acid, which enhances hydrolysis resistance and steric hindrance, allowing for stable toner production in an aqueous medium with improved storage stability and fixing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wet process is used to produce toner containing polyester, then particle size control is improved, but ester bond hydrolysis occurs leading to deteriorated storage stability and fixing property
Solution Approach 1:
The patent changes the chemical structure parameters of the polyester by incorporating specific monomers (alkyl succinic acid with 9-14 carbon atoms, alkenyl succinic acid with 9-14 carbon atoms, and aromatic succinic acid) in controlled amounts. This structural modification increases steric hindrance around ester bonds, making them resistant to hydrolysis while allowing the wet process to be used for particle formation.
Solution Approach 2:
The patent creates a composite polyester system combining multiple carboxylic acid components with specific alcohol components. This composite structure provides both the desired particle size control through wet processing and enhanced hydrolysis resistance through the synergistic effect of different monomer units with varying steric hindrance characteristics.
2Reliability
If polyester with long carbon chain is used to improve fixing property, then fixing property is improved, but particle size control becomes difficult during pulverization
Solution Approach 1:
The patent optimizes the carbon chain length parameter by specifying 9-14 carbon atoms for the alkyl and alkenyl groups, rather than using very long chains. This optimized parameter range provides sufficient fixing property while maintaining adequate particle size control during the melt-kneading and pulverizing process.
Solution Approach 2:
The patent introduces aromatic succinic acid as a specific component that provides local structural characteristics different from the aliphatic succinic acid components. This local quality enhancement improves fixing property without compromising the overall particle size control capability of the polyester system.
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 approach results in a toner with enhanced hydrolysis resistance, storage stability, and fixing properties, maintaining a broad molecular weight distribution and preventing ester bond hydrolysis, even when formed in an aqueous medium.
Implementation Method 1
the polyester is produced by polycondensing an alcohol component with a carboxylic acid component containing at least one compound selected from the group consisting of an alkyl succinic acid and an alkenyl succinic acid
Implementation Method 2
when a toner containing a polyester as a resin binder is produced by the wet process, an ester bond of the polyester tends to be hydrolyzed in a solution
Data Source
AI summary
The present invention relates to a polyester having an excellent hydrolysis resistance even when used in a process for producing a toner for electrophotography which includes a step of forming a raw material into particles in an aqueous medium, and a toner for electrophotography which contains the polyester and is excellent in storage stability and fixing property. There are provided a polyester for a toner for electrophotography which is used in a process for producing a toner including a step of forming a raw material component into particles in an aqueous medium or a solution, and produced by polycondensing an alcohol component with a carboxylic acid component containing at least one compound selected from the group consisting of an alkyl succinic acid and an alkenyl succinic acid, as well as a toner for electrophotography which contains the polyester.