Inkjet Ink Resin Stability on Plasticized Surfaces

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Solution Overview

Problem

Inkjet prints containing plasticizers tend to dissolve and become blurred over time due to the solubility of resin in the plasticizer, leading to unstable markings without the need for ultraviolet irradiation for curing.

Innovation Solution

An ink composition using a resin with high hydroxyl or carboxyl groups, which are insoluble in plasticizers like DEHP, combined with a conductive agent and a leveling agent, ensuring the ink's stability and adhesion without requiring UV curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a resin soluble in MEK is used in the ink, then the ink dries quickly after printing, but the resin dissolves in the plasticizer and the printed dots become blurred or lost over time

Engineering Contradiction:
Improvedrying speedVSAvoidprint stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the resin by selecting specific resins with particular solubility characteristics - resins that are soluble in MEK (for quick drying) but insoluble in plasticizers (for long-term stability). This parameter-based selection resolves the contradiction between drying speed and print stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite ink formulations combining specific resins (such as polyvinyl butyral, polyvinyl acetal, or styrene-acrylic copolymer resins) with pigments and solvents. This composite approach ensures both quick drying through MEK solubility and long-term stability through plasticizer insolubility.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If plasticizer is added to the resin material to improve flexibility, then the material becomes flexible, but the plasticizer seeps out and dissolves the ink resin causing print degradation

Engineering Contradiction:
Improvematerial flexibilityVSAvoidplasticizer migration
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of plasticizer migration into a beneficial selection criterion by choosing resins that are specifically insoluble in plasticizers. The plasticizer migration, which would normally harm the print, becomes a test that validates the suitability of the selected resin, ensuring long-term print stability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional ink formulations are used on plasticized materials, then the printing process is simple, but the prints become blurred and unstable over prolonged periods

Engineering Contradiction:
Improveprinting process simplicityVSAvoidprint stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent maintains printing process simplicity while changing the resin parameter selection - specifically choosing resins with dual solubility characteristics (soluble in MEK, insoluble in plasticizers). This parameter change ensures both ease of manufacture and long-term reliability without complicating the printing process.

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 maintains stable prints over a prolonged period without UV irradiation, preventing ink transfer and maintaining print quality on materials with plasticizers.

Implementation Method 1

a resin with high hydroxyl or carboxyl groups, which are insoluble in plasticizers like DEHP

Methodology Applied
Scientific EffectInsolubility:

Data Source

PatentEP2980170B1Ink for inkjet printer and printed material
Publication Date: 2021.05.05 HITACHI IND EQUIP SYST CO LTD
  • EP2980170B1 patent drawingFigure 1~2
  • EP2980170B1 patent drawingFigure 3~4
  • EP2980170B1 patent drawing

AI summary

In an ink for an inkjet printer of an electrostatic charging control type, the ink including a resin, a pigment, a conductive agent, and a solvent, for the resin, one that contains carboxyl groups or hydroxyl groups is used. Thus, an ink print applied to a material including a large quantity of a plasticizer can be made stable over a prolonged period of time without subjecting the ink print to an ultraviolet irradiation or other special treatments.