Ink Set Adhesion on Non-Permeable Films via Pretreatment

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Solution Overview

Problem

Inkjet recording on non-permeable recording media, such as OPP films, often results in void defects and low adhesion due to ink repulsion and poor wet spreadability, leading to image peeling issues.

Innovation Solution

An ink set comprising inkjet ink with anionic urethane resin particles and a pretreatment liquid containing nonionic urethane resin, (meth)acrylic resin, and polyester resin particles, which form a pretreatment coating film that enhances adhesion and wet spreadability by optimizing the affinity between the ink and the recording medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water-based inkjet ink is used on non-permeable recording medium, then image formation is achieved, but ink is repelled causing void defects and low adhesion

Engineering Contradiction:
Improveimage adhesionVSAvoidink repulsion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A pretreatment liquid containing specific resin particles (polyester resin, polyacrylic resin, and polyvinyl alcohol in defined ratios) is applied to the non-permeable recording medium before inkjet printing. This pretreatment layer acts as an intermediary between the water-based ink and the hydrophobic recording medium surface, improving wet spreadability and adhesion while preventing ink repulsion and void defects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention optimizes the particle size distribution and composition ratios of resin particles in the pretreatment liquid. Specifically, it controls the volume median diameters and mass ratios of different resin particles to achieve optimal surface properties that enable adequate ink wetting and adhesion on non-permeable media without causing repulsion or void defects.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If inkjet ink is applied to non-permeable recording medium, then image is formed, but image peels off upon rubbing

Engineering Contradiction:
Improveimage adhesionVSAvoidimage strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The pretreatment liquid uses a composite system of multiple resin particles (polyester resin, polyacrylic resin, and polyvinyl alcohol) with specific particle size distributions. This composite material approach creates a multi-functional pretreatment layer that simultaneously provides adhesion promotion, wet spreadability enhancement, and mechanical strength to prevent image peeling during rubbing.

Inventive Principle:
Principle #40Composite materials

3Reliability

If pretreatment liquid with resin particles is applied, then adhesion and wet spreadability are improved, but device complexity increases

Engineering Contradiction:
Improveimage adhesionVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pretreatment liquid is applied in advance to the recording medium before the actual inkjet printing process. This preliminary action prepares the surface with optimal adhesion and wetting properties, allowing the subsequent inkjet printing to proceed normally without requiring complex real-time adjustments during the main printing process.

Inventive Principle:
Principle #10Preliminary action

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 set achieves excellent adhesion and wet spreadability on non-permeable media, preventing image peeling and ensuring stable image formation.

Implementation Method 1

The pretreatment liquid contains nonionic urethane resin particles, (meth)acrylic resin particles, and polyester resin particles, which form a pretreatment coating film that enhances adhesion and wet spreadability by optimizing the affinity between the ink and the recording medium

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The pretreatment coating film that enhances adhesion and wet spreadability by optimizing the affinity between the ink and the recording medium

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentUS20240026181A1Ink set and inkjet recording method
Publication Date: 2024.01.25 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

An ink set includes an inkjet ink and a pretreatment liquid. The inkjet ink contains a pigment, anionic urethane resin particles, and an aqueous medium. The pretreatment liquid contains nonionic urethane resin particles, (meth)acrylic resin particles, and polyester resin particles.