Photocurable Inkjet Ink Composition for Resin Adhesion and Tack-Free Cure

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Solution Overview

Problem

Existing photocurable inkjet ink compositions fail to provide excellent curability, tackiness, adhesion, abrasion resistance, water resistance, and ethanol resistance when printed on various resin base materials, and do not consider the solubility of photopolymerization initiators in the composition.

Innovation Solution

A specific compositional makeup is employed, including 30.0% by mass or higher of vinyl methyl oxazolidinone, N,N-dimethylacrylamide, and benzyl acrylate, 15.0% by mass or higher of saturated hydrocarbon group-containing monomers, 3.5% by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, a ratio of ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide to bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide between 0.3 to 1.5, 0.5 to 15.0% by mass of amine-modified oligomer, and the inclusion of a colorant, with optional additives to enhance properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional photocurable inkjet ink compositions containing TPO-L and Irgacure 819 are used, then the ink can be formulated with known components, but the composition fails to provide excellent curability, tackiness, adhesion, abrasion resistance, water resistance, and ethanol resistance on various resin base materials

Engineering Contradiction:
Improvecurability and performance on resin base materialsVSAvoidperformance across various resin types
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent combines multiple photopolymerization initiators (TPO-L and Irgacure 819) with specific monomers (N-vinylcaprolactam, isobornyl acrylate, isodecyl acrylate) and resin components to create a composite ink formulation that achieves excellent performance on diverse resin base materials including vinyl chloride-based polymers and ethylene-vinyl acetate copolymers

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the mass ratios of key components: TPO-L (6 parts), Irgacure 819 (1 part), N-vinylcaprolactam, isobornyl acrylate, and isodecyl acrylate to achieve the desired balance of curability, adhesion, and resistance properties across different resin substrates

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the ink composition is optimized for curability and adhesion, then performance on resin materials improves, but the solubility of photopolymerization initiators in the composition is not adequately considered

Engineering Contradiction:
Improvecurability and adhesionVSAvoidsolubility stability of photopolymerization initiators
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses N-vinylcaprolactam as a mediator component that facilitates the solubility of photopolymerization initiators TPO-L and Irgacure 819 in the ink composition, ensuring homogeneous distribution and stable performance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent carefully controls the concentration of photopolymerization initiators (TPO-L at 6 parts by mass, Irgacure 819 at 1 part by mass) to maintain optimal solubility and reactivity balance in the ink formulation

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the ink is designed for use on polymer sheets for outdoor billboard ads, then the application versatility is improved, but the requirements for lightweight, strong, durable, rain-resistant, and inexpensive properties create multiple conflicting constraints

Engineering Contradiction:
Improvesuitability for outdoor billboard applicationsVSAvoidnumber of conflicting performance requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent develops a universal photocurable inkjet ink composition that simultaneously satisfies multiple outdoor billboard requirements: lightweight (polymer sheet substrate), strong and durable (excellent adhesion and abrasion resistance), rain-resistant (water resistance), and cost-effective (using commercially available components like TPO-L and Irgacure 819)

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 composition achieves low viscosity, excellent photopolymerization initiator solubility, no tack on the cured coated film surface, and superior adhesion, abrasion resistance, water resistance, and ethanol resistance, while preventing banding of the coating film.

Implementation Method 1

photocurable inkjet printing ink composition

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS12509600B2Photocurable inkjet printing ink composition
Publication Date: 2025.12.30 SAKATA INX

AI summary

A photocurable inkjet printing ink composition satisfies requirements A to F: A: the total content of compounds selected from vinyl methyl oxazolidinone, N,N-dimethylacrylamide, benzyl acrylate, and N-vinylcaprolactam, is 30.0% by mass or higher; B: the total content of compounds selected from saturated hydrocarbon group-containing monofunctional monomers with 6 or more carbon atoms and saturated hydrocarbon group-containing polyfunctional monomers with 6 or more carbon atoms is 15.0% by mass or higher in the photocurable inkjet printing ink composition; C: the content of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is 3.5% by mass or higher; D: the total content of ethoxy (2,4,6-trimethylbenzoyl)phenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is 6.0 to 12.0% by mass, and their ratio is 0.3 to 1.5; E: the content of amine-modified oligomer is 0.5 to 15.0% by mass in the photocurable inkjet printing ink composition; and F: a colorant is included.