Toner Shell Layer Styrene-Acryl Polyester Resin Fixing
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Solution Overview
Problem
Conventional toners for electrostatic image development face challenges in achieving both low-temperature fixing ability and high-temperature storage stability, while also ensuring excellent charge properties and shatter resistance, especially in high-speed printing machines.
Innovation Solution
A toner with a shell layer containing a styrene-acryl-modified polyester resin is developed, where the styrene-acrylic polymer segment is bonded to the terminal of a polyester segment, with a content of 5% to 30% by mass, and an aliphatic unsaturated dicarboxylic acid is used to improve affinity and emulsion stability, forming a uniform and thin shell layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a polyester resin is used as shell layer material to achieve low softening point and high glass transition point, then low-temperature fixing ability is improved, but affinity for styrene-acrylic resin is poor causing shell layer formation difficulty
Solution Approach 1:
The invention modifies the polyester resin by introducing a styrene-acrylic polymer segment to create a copolymer structure. This chemical parameter change enables the resin to simultaneously achieve low softening point (for low-temperature fixing) and high glass transition point (for storage stability), while the styrene-acrylic segment provides compatibility with the core particle resin for proper shell layer formation.
Solution Approach 2:
The invention creates a composite resin structure by combining polyester segments (providing thermal stability and high Tg) with styrene-acrylic polymer segments (providing affinity and low softening point). This composite material approach allows the shell layer resin to exhibit multiple desirable properties that cannot be achieved by a single polymer type alone.
2Reliability
If styrene-acrylic resin is used as binder resin for core particles to achieve good charge property, then charge property is improved, but affinity with polyester resin shell layer is poor causing shell layer peeling
Solution Approach 1:
The shell layer resin is chemically modified to contain a styrene-acrylic polymer segment that is structurally compatible with the styrene-acrylic binder resin in the core particles. This parameter change in the shell resin composition creates molecular-level affinity between the core and shell, preventing peeling while maintaining the charge properties of the styrene-acrylic component.
3Ease of manufacture
If conventional pulverization process is used to produce toner to achieve simple manufacturing, then ease of manufacture is improved, but particle size distribution is not sharp reducing image quality
Solution Approach 1:
The invention segments the toner production process into two distinct stages: first forming core particles with styrene-acrylic binder resin, then separately forming the shell layer with the modified polyester resin. This segmentation allows independent control of each particle component, enabling sharp particle size distribution through controlled aggregation and fusion bonding while maintaining manufacturing feasibility.
4Reliability
If shell layer is made thin to improve charge property, then charge property is improved, but high-temperature storage stability is insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the shell layer resin by incorporating styrene-acrylic polymer segments into the polyester structure. This enables the formation of an ultra-thin shell layer (5-50 nm) that maintains sufficient storage stability through the high Tg polyester backbone while the thin configuration exposes more core particle surface for improved charge properties.
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 toner achieves sufficient low-temperature fixing ability, high-temperature storage stability, and excellent charge properties, preventing shell layer peeling and ensuring high-quality images even in high-speed machines.
Implementation Method 1
an emulsion polymerization aggregation process has been proposed as a production process capable of optionally controlling the shape and particle size distribution of toner particles. According to this process, a dispersion of fine colorant particles and optionally a dispersion of fine wax particles are mixed with an emulsified dispersion of fine binder resin particles, these fine particles are aggregated with stirring by, for example, adding a flocculant or controlling a pH, and the aggregated particles are further fusion-bonded by heating
Implementation Method 2
When the glass transition point (Tg) and molecular weight of the binder resin are lowered for lowering the melting temperature and melt viscosity of the binder resin
Implementation Method 3
The polyester resin has the advantage that a design for a low softening point is easily made while retaining a high glass transition point compared with a styrene-acrylic resin
Implementation Method 4
the styrene-acryl-modified polyester resin is obtained by bonding a styrene-acrylic polymer segment to a terminal of a polyester segment
Implementation Method 5
an aliphatic unsaturated dicarboxylic acid is used to improve affinity and emulsion stability
Data Source
AI summary
Disclosed is a toner for electrostatic image development that satisfies both low-temperature fixing ability and excellent high-temperature storage stability, achieves excellent charge property and shatter resistance, and consequently can form a high-quality image even by a high-performance machine such as a high-speed machine.The toner is composed of toner particles obtained by forming a shell layer containing a styrene-acryl-modified polyester resin on the surface of each of core particles comprising a binder resin containing at least a styrene-acrylic resin. The styrene-acryl-modified polyester resin is obtained bonding a styrene-acrylic polymer segment to a terminal of a polyester segment, and the content of the styrene-acrylic polymer segment in the styrene-acryl-modified polyester resin is 5% by mass or more and 30% by mass or less.