Ink Composition Dye Migration Control via IOB Parameter

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Solution Overview

Problem

W/O type emulsion inks used in writing instruments experience reduced emulsion dispersibility and shelf life when stored in containers, leading to compromised writing properties over time.

Innovation Solution

An ink composition with an aqueous component containing water, a thixotropic agent, a polyhydric alcohol, and a pigment, dispersed in an oil component with dyes and non-dye components, where the IOB value for all dyes is no greater than 0.9, ensuring stable dispersion and extended shelf life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional W/O type emulsion inks are stored in storage containers, then the ink composition maintains initial emulsion stability, but the emulsion dispersibility deteriorates over time

Engineering Contradiction:
Improveemulsion dispersibilityVSAvoidshelf life
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by carefully controlling the IOB value of dyes in the oil component to be no greater than 0.9, and managing the difference between IOB values of dyes and non-dye components to be no greater than 0.3. These parameter adjustments prevent dye migration into the aqueous component during storage, maintaining emulsion dispersibility and extending shelf life without compromising writing properties

Inventive Principle:
Principle #35Parameter changes

2Reliability

If dyes with high IOB values are used in the oil component, then the ink composition achieves good initial writing properties, but the dyes migrate into the aqueous component during storage, reducing emulsion stability

Engineering Contradiction:
Improvewriting property consistencyVSAvoidemulsion dispersibility
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent resolves this contradiction by changing the parameter of IOB value for dyes to be no greater than 0.9, and the difference between dye and non-dye component IOB values to be no greater than 0.3. This parameter control prevents dye migration while maintaining writing properties, ensuring both reliability and stability are achieved simultaneously

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 composition maintains excellent dispersibility and writing properties for extended periods, even during storage, by controlling dye migration and enhancing the stability of the emulsion, resulting in superior shelf life and writing performance.

Implementation Method 1

an aqueous component containing water, a thixotropic agent, a polyhydric alcohol and a pigment

Methodology Applied
Scientific EffectThixotropy: Thixotropy

Data Source

PatentEP2159273B1Ink composition for writing instrument and writing instrument
Publication Date: 2012.07.04 ZEBRA
  • EP2159273B1 patent drawingFigure 1
  • EP2159273B1 patent drawing

AI summary

The ink composition for a writing instrument according to the invention has an aqueous component containing water, a thixotropic agent, a polyhydric alcohol and a pigment, dispersed in an oil component having dyes and non-dye components, wherein the IOB value for all of the dyes in the oil component is no greater than 0.9.