White Ink Viscosity Control via Phase Change Resin
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Solution Overview
Problem
Digital offset printing inks, particularly white inks, face challenges in achieving suitable viscosity and transfer properties due to high pigment concentrations and thicker layers, making it difficult to meet rheological specifications and ensure efficient image transfer.
Innovation Solution
A white ink composition incorporating a polyester resin with a crystalline structure that undergoes a phase change at specific temperatures, combined with acrylate/methacrylate monomers, photoinitiators, fillers, and white colorants, which modifies viscosity and enhances transfer properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high pigment concentration is used in white ink to achieve high opacity, then opacity is improved, but viscosity increases making transfer difficult
Solution Approach 1:
The patent changes the physical state parameters of the ink by incorporating phase change materials that transition between solid and liquid states at specific temperatures. This allows the ink to have high viscosity (for transfer) at printing temperature and lower viscosity (for handling) at storage temperature, resolving the contradiction between opacity and transferability
Solution Approach 2:
The patent uses composite ink formulations combining pigment particles, phase change materials, and binder resins. This composite structure allows the ink to simultaneously achieve high opacity from pigments while the phase change components modulate viscosity to enable proper transfer, resolving the contradiction between these two properties
2Area of stationary object
If thicker ink layer is used to cover large areas, then coverage is improved, but transfer efficiency decreases
Solution Approach 1:
The patent introduces dynamic viscosity control through phase change materials that respond to temperature variations during the printing process. The ink transitions from a more viscous state during application to a less viscous state during transfer, enabling thick layers to be applied and then efficiently transferred, resolving the contradiction between coverage area and transfer efficiency
3Ease of operation
If viscosity is increased to improve transfer, then transfer is improved, but ink flow and wetting properties worsen
Solution Approach 1:
The patent exploits phase transitions of the ink components at different temperatures. At storage temperature, the ink maintains higher viscosity for better transfer, while at printing temperature, the phase change materials transition to a state that improves flow and wetting properties, resolving the contradiction between transfer and wetting
Solution Approach 2:
The patent utilizes periodic temperature variations during the printing process to cycle the ink between different viscosity states. This periodic change in physical state allows the ink to exhibit high viscosity during transfer phases and lower viscosity during flow and wetting phases, resolving the contradiction between these opposing 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 ink composition achieves improved viscosity control, efficient transfer of 90% of the image layer, reduces ghost images, and is suitable for food contact, with enhanced rheological properties and low odor, while maintaining compatibility with printing materials.
Implementation Method 1
at least one polyester resin that exhibits a crystalline structure at temperatures at or below a recrystallization temperature and that has a melting temperature below 120°C
Implementation Method 2
that has a melting temperature below 120°C
Implementation Method 3
at least one photoinitiator; an ink vehicle comprising at least one compound chosen from acrylate monomers, methacrylate monomers, acrylate oligomers and methacrylate oligomers
Data Source
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AI summary
A white ink composition is disclosed. The white ink composition comprises an ink vehicle comprising at least one compound chosen from acrylate monomers, methacrylate monomers, acrylate oligomers and methacrylate oligomers; at least one polyester resin that exhibits a crystalline structure at temperatures at or below a recrystallization temperature and that has a melting temperature below 120°C; at least one photoinitiator; a filler comprising at least one component chosen from clay fillers and silica fillers; and at least one white colorant.