White Ink Composition for LED Curing and Transfer
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Solution Overview
Problem
Existing digital offset printing white ink compositions are unsuitable for LED curing, facing challenges in achieving acceptable opacity and robustness, and struggle with transfer from anilox rollers to substrates.
Innovation Solution
A white ink composition comprising acrylate or methacrylate monomers, oligomers, a solid polyol adhesive resin, and a photoinitiator, designed to be compatible with LED curing sources, ensuring good wetting, transfer, and adhesion properties, and providing high opacity and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white ink composition uses high pigment concentration to achieve high opacity, then opacity is improved, but transfer from anilox roller to substrate becomes difficult
Solution Approach 1:
The patent changes the chemical parameters of the ink vehicle by using radiation-curable resins (acrylate, methacrylate, vinyl) with specific functional groups and molecular weights. This allows the ink to maintain high pigment concentration (60-80 wt% solids) while achieving proper rheological properties for transfer, resolving the contradiction between opacity and transferability
Solution Approach 2:
The patent creates a composite ink system combining radiation-curable resin components with high pigment loading. The multi-component resin system (comprising reactive diluents, oligomers, and crosslinkers) works synergistically to enable both high opacity through pigment concentration and effective transfer through controlled viscosity and surface tension
2Reliability
If white ink composition is designed for Hg (D-bulb) light source curing, then curing is achieved, but compatibility with LED curing sources is poor
Solution Approach 1:
The patent selects photoinitiators and resin components with absorption spectra matched to LED emission wavelengths (365nm, 385nm, 395nm, 405nm). By changing the chemical composition parameters to include initiators like TPO, 184, and 379 that specifically absorb LED wavelengths, the ink achieves reliable curing with LED sources while maintaining adaptability across different LED types
Solution Approach 2:
The patent creates a universal ink formulation that can be cured by multiple light sources (Hg bulbs and various LED wavelengths). The multi-component photoinitiator system and broad-spectrum reactive resins provide multi-functionality, allowing the same ink composition to work reliably across different curing technologies without requiring separate formulations
3Area of stationary object
If thicker ink layer is used to cover large areas, then coverage is improved, but transfer difficulty increases
Solution Approach 1:
The patent formulates the ink with radiation-curable components that allow dynamic control of ink layer thickness and viscosity during the printing process. The ink can be applied as a thicker layer for coverage but cures rapidly upon UV/LED exposure, preventing transfer issues that would normally occur with thick ink layers
Solution Approach 2:
The patent uses reactive diluents and oligomers with specific viscosity characteristics that allow the ink to flow properly during application for大面积 coverage, then rapidly crosslink upon curing. This parameter control enables thick ink layers to be applied and transferred effectively without the usual transfer difficulties
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 efficient transfer and high opacity prints with improved adhesion and chemical resistance, suitable for LED curing, addressing the limitations of prior compositions.
Implementation Method 1
The 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 photoinitiator
Implementation Method 2
forming a latent image by removing the dampening fluid from selective locations on the imaging member surface to form hydrophobic non-image areas and hydrophilic image areas
Data Source
AI summary
A 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 polyol adhesive resin that is solid at 25° C.; at least one photoinitiator; and at least one white colorant. A method of printing the ink composition is also disclosed.