Toner Binder Resin Composition with Low IV PET
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Solution Overview
Problem
Conventional resin binder compositions for toners using polyethylene terephthalate (PET) face issues with initial rise in charging and filming resistance due to high molecular weight PET, leading to uneven polymer structures and low mechanical strength, especially during high-speed printing and low-temperature fusing.
Innovation Solution
A resin binder composition is developed using a polyester resin polycondensate of polyethylene terephthalate with a lower intrinsic viscosity (IV) value (0.40-0.68) and an aliphatic diol with a hydroxyl group bonded to a secondary carbon atom, which improves dispersion and mechanical strength, enhancing low-temperature fusing ability and filming resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight PET is used to improve durability, then reliability is improved, but manufacturing precision deteriorates due to uneven polymer structure
Solution Approach 1:
The patent changes the intrinsic viscosity parameter of PET from conventional high values (>0.75) to a specific range of 0.40-0.68. This parameter modification enables more uniform depolymerization during polyester resin synthesis, creating a more homogeneous polymer structure while maintaining adequate durability for toner applications.
Solution Approach 2:
The patent creates a composite polyester resin system combining depolymerized PET fragments with aliphatic diol units (40-100 mol%). This composite structure integrates the durability benefits of PET with the uniformity and low-temperature fusing properties of aliphatic diols, resolving the contradiction between reliability and manufacturing precision.
2Reliability
If high molecular weight PET is used to improve durability, then reliability is improved, but initial rise in charging deteriorates
Solution Approach 1:
By reducing the intrinsic viscosity parameter of PET to 0.40-0.68, the patent creates smaller, more uniformly distributed polymer fragments that depolymerize more completely. This results in faster charging response while maintaining durability through the overall polyester resin network structure.
Solution Approach 2:
The composite polyester resin incorporating aliphatic diol units (40-100 mol%) provides rapid charging capability through the aliphatic segments while the PET backbone maintains durability. This composite approach resolves the contradiction between reliability and initial rise in charging speed.
3Temperature
If short-chained aliphatic diol is used to improve low-temperature fusing ability, then temperature performance is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent creates a composite polyester resin where aliphatic diol units (providing low-temperature fusing ability) are combined with PET segments (providing mechanical strength). The synergistic composite structure achieves both low-temperature fusing performance and adequate mechanical strength, resolving the contradiction between these two properties.
Solution Approach 2:
The patent introduces local aliphatic diol segments (40-100 mol%) within the polyester resin structure to provide low-temperature fusing ability at specific locations, while the overall PET-based polymer matrix maintains mechanical strength. This local quality approach allows different regions of the polymer to fulfill different functional 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
The composition achieves improved low-temperature fusing ability, initial rise in charging, and filming resistance on photoconductors by evenly dispersing PET with lower molecular weight, addressing the limitations of conventional PET-based resin binders.
Implementation Method 1
carrying out a polycondensation reaction of a polyethylene terephthalate, a carboxylic acid component, and an alcohol component in the presence of an esterification catalyst
Data Source
AI summary
A resin binder composition for a toner, containing a polyester resin, which is a polycondensate of a polyethylene terephthalate, a carboxylic acid component, and an alcohol component, wherein the polyethylene terephthalate contains a polyethylene terephthalate having a IV value of 0.40 or more and 0.75 or less, and wherein the alcohol component contains an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom having 2 or more carbon atoms and 4 or less carbon atoms in an amount of 40% by mol or more and 100% by mol or less, a method for producing a polyester resin contained in the resin binder composition, and a toner for electrophotography containing the resin binder composition. The resin binder composition for a toner of the present invention is suitably used in the toner for electrophotography usable in development or the like of latent images formed in, for example, method for electrostatic image development, electrostatic recording method, electrostatic printing method or the like.