Multilayer Coat Inkjet Printing Adhesion

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Solution Overview

Problem

Decorative laminates for buildings face challenges in achieving high designability with excellent adhesive properties, water resistance, and weathering resistance, particularly due to issues with inkjet printing, where the use of water-based inks and coatings leads to ink running and delamination, and active energy ray-curing type inks have low adhesion to substrates.

Innovation Solution

A multilayer coat is produced by forming an undercoat layer with a specific surface free energy of 20-50 mN/m, followed by inkjet printing with an active energy ray-curing type ink having a surface tension of 20-35 mN/m, and then applying a top coating material with a surface tension of 20-50 mN/m, ensuring excellent adhesion and resistance without delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If water-based inks and coatings are used for environmental reasons, then environmental impact is reduced, but adhesive properties and water resistance deteriorate causing delamination

Engineering Contradiction:
Improveenvironmental impactVSAvoidadhesive properties
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the coating materials, specifically incorporating silane-modified polymers and isocyanate compounds that react to form cross-linked structures. This chemical parameter change allows water-based coatings to achieve strong adhesion and water resistance without using organic solvents, thus resolving the contradiction between environmental friendliness and adhesive performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite coating materials combining silane-modified polymers with isocyanate cross-linking agents. This composite approach creates a multi-functional coating system that simultaneously provides environmental benefits (water-based), strong adhesion (through chemical bonding), and water resistance (through cross-linked network structure), resolving the contradiction between harmful factors and strength

Inventive Principle:
Principle #40Composite materials

2Loss of time

If active energy ray-curing type inks are used for quick drying, then drying time is reduced, but adhesion to substrate deteriorates

Engineering Contradiction:
Improvedrying timeVSAvoidadhesion to substrate
Core Design Contradiction:
Loss of timeVSStrength

Solution Approach 1:

The patent modifies the chemical composition of the active energy ray-curing ink by incorporating silane-modified polymers with specific functional groups that provide both rapid curing capability and strong substrate adhesion. The silane groups form chemical bonds with the substrate while the polymer structure enables quick curing upon irradiation, resolving the contradiction between drying speed and adhesion strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The silane-modified polymer acts as an intermediary between the active energy ray-curing mechanism and the substrate. It provides anchoring groups that bond to the substrate while maintaining compatibility with the photopolymerization process, thus mediating between the conflicting requirements of quick drying and strong adhesion

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If prime coat surface is made thick for protection, then water resistance is improved, but ink absorbability deteriorates causing ink spreading

Engineering Contradiction:
Improvewater resistanceVSAvoidimage precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different functional properties to different parts of the coating system. The undercoat layer provides thick protective function with water resistance, while the topcoat layer provides thin functional properties for ink absorbability and image precision. This local differentiation resolves the contradiction between water resistance and image precision

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the coating into multiple functional layers: an undercoat layer for protection and water resistance, and a topcoat layer for ink reception and image formation. This segmentation allows each layer to optimize its specific function without compromising the other, resolving the contradiction between water resistance and image precision

Inventive Principle:
Principle #1Segmentation

4Strength

If solvent-based coating materials are used for adhesion, then adhesive properties are improved, but environmental impact worsens due to VOC discharge

Engineering Contradiction:
Improveadhesive propertiesVSAvoidVOC discharge
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solvent parameter from organic solvents to water as the primary solvent, while compensating for the loss of adhesion through chemical cross-linking mechanisms. The silane-isocyanate reaction system provides strong adhesive bonds without requiring volatile organic solvents, thus resolving the contradiction between adhesion strength and VOC emissions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the physical adhesion mechanism provided by organic solvents with a chemical bonding mechanism using silane-isocyanate cross-linking. This substitution eliminates the need for VOC-based adhesion while maintaining or improving bond strength, resolving the contradiction between adhesive properties and environmental impact

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

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 method results in a multilayer coat with high designability, excellent adhesive properties, and enhanced water and weathering resistance, preventing ink running and delamination, while reducing environmental impact through the use of water-based materials.

Implementation Method 1

coating the undercoat layer with an active energy ray-curing type ink; curing the active energy ray-curing type ink through active energy ray irradiation

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a multilayer coat comprising an undercoat layer, an ink layer, and a top coat layer; excellent adhesive properties

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9138779B2Multilayer coat and method for producing the same
Publication Date: 2015.09.22 DAI NIPPON TORYO CO LTD

AI summary

Disclosed is a method for producing a multilayer coat characterized by including the steps of coating a substrate with an undercoating material to form an undercoat layer, coating the undercoat layer with an active energy ray-curing type ink in an ink-jet system, curing the active energy ray-curing type ink through active energy ray irradiation, and coating the cured active energy ray-curing type ink with a top coating material to form a top coat layer, wherein the surface free energy of the undercoat layer is γs=20-50 mN/m, the active energy ray-curing type ink has a surface tension at 40° C. of 20-35 mN/m, and the top coating material has a surface tension at 25° C. of 20-50 mN/m, as well as a multilayer coat obtained by the production method.