Curable Inkjet Ink for Vacuum Formed Plastic Substrates

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Solution Overview

Problem

Current inkjet inks are unable to digitally print onto plastic substrates without cracking or distorting during thermal processing, limiting their application in digital printing for three-dimensional plastic constructions.

Innovation Solution

A curable inkjet ink composition containing a mono-functional monomer with a molecular weight of 100 g/mole to 600 g/mole, an acrylic polymer or copolymer with an acid number below 20, and a polymerizable diluent like Vinylpyrrolidone, which allows the ink to form chemical, mechanical, or combined bonds with the plastic substrate, enabling continuous elongation during thermal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inkjet inks are used for digital printing onto plastic substrates, then the printing process is simple and fast, but the printed images crack or cannot elongate under thermal conditions

Engineering Contradiction:
Improvethermal elongation capabilityVSAvoidprinting process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by incorporating specific functional monomers (acrylates, methacrylates, vinyl monomers) with controlled molecular weights and ratios. These parameter changes enable the ink to achieve both thermal elongation capability and printability without requiring complex processing steps

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite ink system combining multiple monomer types (polymerizable diluent, reactive monomer, functional monomer) that work synergistically. This composite formulation provides thermal elongation, adhesion, and jetability properties simultaneously, resolving the contradiction between performance and manufacturing simplicity

Inventive Principle:
Principle #40Composite materials

2Reliability

If screen printing is used for plastic substrates, then thermal elongation is achieved, but digital printing capability is lost

Engineering Contradiction:
Improvethermal elongation capabilityVSAvoiddigital printing capability
Core Design Contradiction:
ReliabilityVSExtent of automation

Solution Approach 1:

The patent replaces the mechanical screen printing process with a digital inkjet printing system. The key enabler is the specially formulated ink composition that contains monomers designed to elongate under thermal conditions, allowing the automated digital printing process to achieve results previously only possible with manual screen printing

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

Solution Approach 2:

By changing the chemical parameters of the ink (monomer selection, molecular weight distribution, functional group composition), the invention enables digital printing ink to exhibit thermal elongation properties similar to screen printing inks, thus achieving automation without sacrificing thermal performance

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If polymerizable diluents are used to reduce viscosity for jetting, then ink jetability is improved, but cross-linking upon curing causes cracking during thermal processing

Engineering Contradiction:
Improveink jetabilityVSAvoidcrack resistance during thermal processing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by using different types of monomers with specific functions: polymerizable diluents for jetability, reactive monomers for cross-linking density control, and functional monomers for flexibility and adhesion. This localized functional distribution within the ink formulation allows simultaneous achievement of jetability and crack resistance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the molecular weight and functional group parameters of the monomers used. Lower molecular weight monomers improve jetability, while specific functional groups (carboxyl, hydroxyl, amino) provide flexibility and adhesion that prevent cracking during thermal processing

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 ink composition allows for digital printing onto plastic substrates with excellent durability and thermal elongation properties, preventing cracking and distortion, and enabling the production of three-dimensional plastic objects through vacuum forming and heat-bending.

Implementation Method 1

The mono-functional monomer enables the ink composition to undergo continuous elongation during thermal processing of the plastic substrate

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

enabling the ink to form chemical, mechanical, or combined bonds with the plastic substrate

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP1979172B1High elongation vacuum formable digital ink
Publication Date: 2017.10.11 ELECTRONICS FOR IMAGING INC

AI summary

The present invention includes a curable ink composition for digitally printing onto plastic substrates and three dimensional objects comprising an ink composition comprising a pigment, an acrylic polymer or copolymer having an acid number below about 20 component, a diluent, additives and a mono- functional monomer. The mono-functional monomer may be an aromatic monoacrylate.