Curable Inkjet Ink for Plastic Substrates with Thermal Elongation

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Solution Overview

Problem

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

Innovation Solution

A curable inkjet ink composition containing a pigment, a diluent, an acrylic polymer or copolymer with an acid number below 20, and a mono-functional monomer, which can be cured using UV or LED energy, enabling the ink image to form chemical, mechanical, or combined bonds with the plastic substrate, allowing for continuous elongation during thermal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional inkjet inks are used on plastic substrates, then digital printing can be performed, but the ink images crack or cannot elongate during thermal processing

Engineering Contradiction:
Improveapplicability to plastic substratesVSAvoidcrack resistance during thermal processing
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by incorporating polymerizable diluents that can crosslink upon curing. This transformation allows the ink to develop elastic properties and thermal elongation capability, enabling it to withstand thermal processing of plastic substrates without cracking while maintaining digital printing applicability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink system combining polymerizable diluents, resins, and pigments that form a crosslinked polymer network after curing. This composite structure provides both the adhesion needed for plastic substrates and the elasticity required for thermal elongation, resolving the contradiction between digital printing compatibility and crack resistance

Inventive Principle:
Principle #40Composite materials

2Reliability

If screen printing is used on 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 that uses chemically active inks. The polymerizable diluents and crosslinking mechanisms substitute for the mechanical forcing of ink through screens, enabling digital printing to achieve thermal elongation capabilities previously only available through screen printing

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

Solution Approach 2:

The patent transforms the ink's physical and chemical parameters through polymerizable diluents and UV/heat curing processes. This creates an ink system that maintains the fluidity needed for digital jetting while developing the elastic properties required for thermal elongation, bridging the gap between digital printing automation and thermal processing compatibility

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If polymerizable diluents are used, then low viscosity and jetability are achieved, but crosslinking upon curing reduces flexibility

Engineering Contradiction:
ImprovejetabilityVSAvoidflexibility after curing
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by using mono-functional monomers in specific proportions within the ink formulation. These monomers provide localized flexibility points within the crosslinked network, ensuring that while the ink cures to a durable finish, it retains sufficient elasticity to elongate with the plastic substrate during thermal processing without cracking

Inventive Principle:
Principle #3Local quality

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 excellent exterior durability and thermal elongation of 100% to 900% without cracking or distortion, enabling digital printing on plastic substrates and three-dimensional objects, and reduces the need for screen printing techniques.

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

The curable inkjet ink composition... can be cured using UV or LED energy

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS7427317B2High elongation vacuum formable digital ink
Publication Date: 2008.09.23 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.