Ink Composition VOC Reduction Ejection Stability

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Solution Overview

Problem

Aqueous ink compositions used in inkjet recording methods face challenges with volatile organic compounds (VOC) emission, as penetration agents with higher boiling points improve stability but can lead to ink bleeding and reduced image quality.

Innovation Solution

An ink composition containing 3-methyl-1,5-pentanediol, di(ethylene glycol) 2-ethylhexyl ether, and water, with a 1,2-hexanediol content of 0.5% or less, and a mass ratio of 3-methyl-1,5-pentanediol to di(ethylene glycol) 2-ethylhexyl ether between 13/1 and 67/1, which reduces VOC emission while maintaining high ejection stability and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a penetration agent with higher normal boiling point than 1,2-hexanediol is used, then VOC emission is reduced, but ejection stability deteriorates and image quality decreases

Engineering Contradiction:
ImproveVOC emissionVSAvoidejection stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent uses a composite penetration agent system comprising three specific compounds: 1,2-hexanediol (5-20 mass%), 1,5-pentanediol (70-95 mass%), and 1,6-hexanediol (5-20 mass%). This composite approach combines the advantages of different penetration agents with varying boiling points and penetration capabilities, achieving both low VOC emission and high ejection stability that cannot be obtained with single agents alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent precisely controls the mass ratios of the three penetration agents within specific ranges to optimize performance. By adjusting the proportions of each component, the formulation achieves the optimal balance between penetration power, ejection stability, and VOC emission reduction, demonstrating parameter optimization as a key inventive approach.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If a penetration agent with higher normal boiling point than 1,2-hexanediol is used, then VOC emission is reduced, but image quality deteriorates with increased graininess

Engineering Contradiction:
ImproveVOC emissionVSAvoidimage quality
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The tri-component penetration agent system provides synergistic effects that improve image quality while reducing VOC emission. The combination of 1,2-hexanediol, 1,5-pentanediol, and 1,6-hexanediol creates a balanced formulation that ensures uniform ink distribution and fine image graininess, overcoming the limitations of single high-boiling-point agents.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise mass percentage ranges for each penetration agent component to optimize image quality. This controlled composition ensures that the ink forms high-quality images with minimal graininess while maintaining low VOC emission, demonstrating how parameter control resolves the contradiction between environmental performance and image quality.

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 effectively reduces VOC emission, achieves high ejection stability, and maintains high image quality, even on non-absorbent media, by optimizing the ratio of 3-methyl-1,5-pentanediol to di(ethylene glycol) 2-ethylhexyl ether and limiting 1,2-hexanediol content.

Implementation Method 1

aqueous ink compositions containing water as the base thereof have come into use for ink jet recording apparatuses from the viewpoint of the global environment and safety... contain an alkanediol as a penetration agent so that the ink can be stably ejected

Methodology Applied
Scientific EffectPenetration:

Implementation Method 2

aqueous ink compositions containing water as the base thereof... the ink attached to the recording medium is not easily dried

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3375830B1Ink composition
Publication Date: 2020.01.22 SEIKO EPSON CORP

AI summary

An ink composition contains 3-methyl-1,5-pentanediol, di(ethylene glycol) 2-ethylhexyl ether, and water, and has a 1,2-hexanediol content of 0.5% by mass or less. In the ink composition, the mass ratio of 3-methyl-1,5-pentanediol to di(ethylene glycol) 2-ethylhexyl ether is in the range of 13/1 to 67/1.