Inkjet Ink Formulation for Low Odour Food Packaging
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Solution Overview
Problem
There is a need for low viscosity and ultra-low viscosity inkjet inks that are free from volatile organic solvents and monomers, which are suitable for printing on food packaging to meet the requirements of high resolution and high speed printheads while ensuring low odour and low migration properties.
Innovation Solution
The inkjet ink formulation includes an α,β-unsaturated ether monomer and a low-viscosity difunctional (meth)acrylate monomer, with specific viscosity and boiling point characteristics, along with a colouring agent, to achieve low odour and low migration, and is designed to have a viscosity of less than 30 mPas at 25°C, minimizing the use of other components and excluding volatile organic solvents and most monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional inkjet inks are used, then printing flexibility and ease of use are achieved, but volatile organic solvents and monomers are present causing high odour and migration issues
Solution Approach 1:
The patent changes the chemical composition parameters by replacing volatile organic solvents and conventional monomers with water-soluble polymerizable monomers having specific viscosity characteristics (0.5-6.5 mPas at 25°C). This parameter change eliminates harmful volatile components while maintaining the liquid flow properties needed for inkjet printing flexibility.
Solution Approach 2:
The patent creates a composite ink formulation combining water-soluble polymerizable monomers, photopolymerization initiators, and colorants in specific proportions. This composite material achieves both low viscosity for printing flexibility and elimination of harmful volatile components through the synergistic combination of non-volatile polymerizable components.
2Productivity
If high resolution and high speed printheads are used, then printing precision and productivity are improved, but ink viscosity must be reduced below 30 mPas
Solution Approach 1:
The patent optimizes the viscosity parameter of the ink formulation to fall within 0.5-6.5 mPas at 25°C by selecting specific water-soluble polymerizable monomers. This parameter change enables compatibility with high speed printheads requiring low viscosity for adequate flow and deposition at high printing speeds.
3Quantity of substance
If low viscosity ink is formulated, then compatibility with high speed printheads is achieved, but the ink may lack sufficient film integrity and resilience
Solution Approach 1:
The patent replaces mechanical mixing and physical bonding with photochemical polymerization. The ink contains photopolymerization initiators that trigger crosslinking upon UV exposure, creating a resilient film through chemical bonds rather than mechanical entanglement. This substitution allows low viscosity for printing while ensuring film integrity through photopolymerization.
Solution Approach 2:
The patent formulates a composite material system where water-soluble polymerizable monomers and photopolymerization initiators work together to create a crosslinked polymer film. This composite approach achieves both low viscosity for printing compatibility and sufficient film resilience through photopolymerization-induced crosslinking.
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 provides a flexible and resilient film with low odour and low migration properties, making it suitable for food packaging applications and compatible with high resolution and high speed printheads, while adhering to regulatory standards for food packaging.
Implementation Method 1
By 'radiation-curable' is meant that the material polymerises or crosslinks when exposed to actinic radiation, commonly ultraviolet light, in the presence of a photoinitiator.
Data Source
AI summary
This invention provides an inkjet ink comprising: an α,β-unsaturated ether monomer in which the only radiation-curable functional groups present in the monomer are α,β-unsaturated ether groups;a low- viscosity difunctional (meth)acrylate monomer in which the only radiation-curable functional groups present in the monomer are acrylate groups, wherein the low-viscosity difunctional (meth)acrylate monomer has a viscosity of 0.5 to 6.5 mPas at 25°C; and a colouring agent;wherein the ink contains less than 5% by weight of water and volatile organic solvents in total, and less than 10% by weight of mono-and difunctional monomers in total, other than the α,β-unsaturated ether monomer and the low-viscosity difunctional (meth)acrylate monomer, where the amounts by weight are based on the total weight of the ink, and wherein the ink has a viscosity of less than 30 mPas at 25º C.