Polyester Toner Composition for Low-Temperature Fusing on Plastic Films
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Solution Overview
Problem
Existing electrostatic image development toners struggle to provide high fastness and low-temperature fusing properties when used on plastic films, leading to peeling and thermal shrinkage issues.
Innovation Solution
An electrostatic image development toner containing a crystalline polyester resin with specific structural units and ester group concentration, combined with an amorphous polyester resin and a pigment with controlled NH group amount, enhances cohesive force and compatibility, allowing for high fastness and low-temperature fusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional toners are used on plastic films, then printing can be performed, but the printed coating film is easily peeled off due to smooth surface and lack of anchoring effect
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating polyester resins with specific functional groups (carboxyl, hydroxyl, or amine groups) in controlled amounts. This chemical parameter modification enables strong chemical bonding between the toner and plastic film surface, transforming the physical adhesion problem into a chemical bonding solution that resists peeling.
Solution Approach 2:
The invention uses a composite binder resin system combining polyester resin base components with specific functional group-containing additives. This composite material approach creates a multi-functional binder that provides both adhesion to the smooth plastic surface and controlled reactivity for chemical bonding, solving the peeling issue through material composition optimization.
2Reliability
If conventional toners are thermally fused, then image fixation is achieved, but the plastic films curl and shrink due to heat vulnerability
Solution Approach 1:
The invention modifies the thermal properties of the toner system by selecting polyester resins with specific glass transition temperatures and melting points. The binder resin is designed to become sufficiently pliable at fusing temperatures to enable image fixation, yet the overall system is formulated to cool rapidly after fusing, preventing excessive heat transfer to the plastic film that would cause curling or shrinking.
Solution Approach 2:
The invention employs a rapid fusing and cooling cycle that quickly passes through the critical temperature range where plastic film deformation occurs. The toner is fused at elevated temperatures briefly to achieve image fixation, then rapidly cooled to lock the image in place before the plastic film can undergo thermal deformation, effectively skipping the harmful thermal exposure window.
3Ease of manufacture
If the plastic film surface is smooth, then printing can be performed, but anchoring effect hardly occurs between surface and coating film
Solution Approach 1:
The invention changes the chemical reactivity parameters of the toner binder resin by incorporating polyester resins with specific functional groups (carboxyl, hydroxyl, or amine groups). These functional groups provide chemical anchoring capability that does not depend on surface roughness, enabling strong bonding to smooth plastic film surfaces through chemical affinity rather than mechanical interlocking.
4Reliability
If higher fusing temperature is used, then image fixation is improved, but thermal shrinkage of plastic film increases
Solution Approach 1:
The invention optimizes the thermal transition parameters of the binder resin, specifically the glass transition temperature and melting point. The binder is designed to achieve sufficient softening and flow at relatively low temperatures to enable complete image fixation, eliminating the need for high fusing temperatures that would cause plastic film shrinkage. The rapid cooling capability is also enhanced to quickly stabilize the image at lower temperatures.
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 excellent low-temperature fusing properties and forms a printed coating film with high fastness on plastic films, improving adherence and resistance to thermal shrinkage.
Implementation Method 1
the toner contains a crystalline polyester resin C, an amorphous polyester-based resin A, and a colorant... enhances cohesive force and compatibility
Implementation Method 2
improving adherence and resistance to thermal shrinkage... forms a printed coating film with high fastness
Implementation Method 3
low-temperature fusing properties... allows for high fastness and low-temperature fusing
Implementation Method 4
the fusing temperature is a temperature which is at most 5°C higher than the melting point of the polypropylene film or polyethylene film
Data Source
AI summary
The present invention relates to an electrostatic image development toner containing a crystalline polyester resin C, an amorphous polyester-based resin A, and a colorant, in which the crystalline polyester resin C includes a structural unit derived from an aliphatic diol component containing ethylene glycol and a structural unit derived from an aliphatic dicarboxylic acid component having 10 or more and 14 or less carbon atoms, and has an ester group concentration of 6.5 mmol/g or more and 9.0 mmol/g or less, and the colorant is a pigment having a NH group amount of 6.0 mmol/g or more, the NH group amount being obtained by dividing a total number of -NH- and -NH2 contained in one molecule of the pigment by a molecular weight of the pigment.