Radiation-Curable Water-Based Inkjet Inks for Lightweight Paper Printing

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Solution Overview

Problem

Conventional inkjet printing technologies face challenges due to high costs, limited substrate compatibility, and environmental concerns related to water-based inks, particularly high water content leading to show-through issues on lightweight papers and the need for external heat for drying, which increases energy consumption and processing complexity.

Innovation Solution

Development of radiation-curable, water-based inkjet ink compositions that can be cured by UV or EB radiation without external heat, allowing for improved energy efficiency and reduced viscosity, enabling printing on lightweight papers and various substrates with enhanced adhesion and reduced show-through.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional water-based inkjet inks are used, then the ink can be applied to substrates, but the high water content causes show-through on lightweight papers and requires high temperatures for drying

Engineering Contradiction:
Improvewater contentVSAvoidshow-through
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the water-based ink by incorporating radiation-curable components (such as water-soluble acrylic resins and crosslinking agents) that allow the ink to cure through UV or electron beam radiation. This parameter change enables the ink to achieve adequate film formation and adhesion with reduced water content compared to conventional water-based inks, thereby reducing show-through on lightweight papers while eliminating the need for high-temperature drying.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If conventional water-based inkjet inks are used, then the ink can be applied to substrates, but high temperatures must be applied to dry the inks adequately

Engineering Contradiction:
Improvewater contentVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the thermal drying mechanism (heating) with a radiation-curing mechanism. The ink contains radiation-curable components that undergo polymerization or crosslinking when exposed to UV or electron beam radiation, eliminating the need for high-temperature drying. This substitution of the drying mechanism dramatically reduces energy consumption while maintaining adequate ink film formation and adhesion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional water-based inkjet inks are used, then printing can be performed, but the inks have limited adhesion to a range of substrates

Engineering Contradiction:
Improvesubstrate compatibilityVSAvoidadhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite ink formulations that combine water-based components with radiation-curable components. The water-based aspect provides good adhesion to porous substrates like paper and cardboard, while the radiation-curable components (such as acrylic resins and crosslinking agents) provide enhanced adhesion to non-porous substrates through UV or electron beam curing. This composite approach enables reliable adhesion across a wide range of substrate types.

Inventive Principle:
Principle #40Composite materials

4Reliability

If UV inkjet inks made from hydrophobic monomers and oligomers are used, then adhesion to various substrates is improved, but the inks contain VOCs that create health risks

Engineering Contradiction:
ImproveadhesionVSAvoidVOC content
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by using water-soluble acrylic resins and hydrophilic monomers instead of hydrophobic monomers and oligomers. This parameter change allows the ink to maintain radiation-curable properties while being based on water, thereby eliminating or significantly reducing VOC content. The water-based formulation with radiation-curable components achieves adequate adhesion to various substrates without the health risks associated with VOCs.

Inventive Principle:
Principle #35Parameter changes

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 solution allows for efficient, cost-effective, and environmentally friendly printing on a wide range of substrates, including lightweight papers, with reduced ink usage and energy consumption, enabling 4-color printing and improved tensile strength, while eliminating the need for external heat drying.

Implementation Method 1

Development of radiation-curable, water-based inkjet ink compositions that can be cured by UV or EB radiation without external heat

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

cured by UV or EB radiation

Methodology Applied
Scientific EffectElectron Beam: Electron Beam

Data Source

PatentEP3532549B1New design of an inkjet printing press using curable water-based primers, coatings and inks
Publication Date: 2022.03.09 FILSEN PTY LTD
  • EP3532549B1 patent drawingFigure 1a~1b
  • EP3532549B1 patent drawingFigure 2
  • EP3532549B1 patent drawingFigure 3

AI summary

The invention describes a new design of commercial inkjet press with pre-coating prior to printing which may upgrade the quality of the surface of the substrate and enable it to be printable by all digital printing technologies including inkjet. Also described are curable water-based coatings and inks which may be cured at high speed without the need for external applied heat to dry the water content. The compositions of the invention, when used as coatings or primers, may create a surface on cellulosic substrates and polymeric films which is suitable for printing on by most printing methods including but not limited to inkjet, wet and dry toner systems, lithographic, gravure and flexographic. The primers or coatings may also add up to 15% tensile strength to lightweight papers under 40 GSM. The press design of the invention may produce high quality printed product from low-grade inexpensive paper substrates or polymeric film. The primers and coatings of the invention may allow colour printing, including 4-colour printing, on lightweight papers by conventional water based inkjet inks which papers could previously not be printed with this method; whilst the aqueous, curable inkjet inks of the invention may eliminate many of the shortcomings of conventional radiation curable inkjet inks.