Ink Composition Solvent Distribution Coefficient Skin Sensitivity

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Solution Overview

Problem

Aqueous ink compositions for ink jet recording face issues with skin sensitivity due to biocidal antiseptic and antifungal agents, and stability problems at low temperatures due to the use of certain additives, leading to potential allergic contact dermatitis and nozzle clogging.

Innovation Solution

A liquid composition comprising a glycerin ester with a water-octanol distribution coefficient of 0.8 to 3.0 and an organic solvent with a distribution coefficient of -1.0 to 1.0, along with water and a coloring material, which secures antiseptic performance without biocidal agents and maintains stability at low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antiseptic and antifungal agents are added to aqueous ink composition, then antiseptic performance is improved, but skin sensitivity and allergic contact dermatitis risk increase

Engineering Contradiction:
Improveantiseptic performanceVSAvoidskin sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the antiseptic agent by specifying a distribution coefficient of water-octanol between 0.8 to 3.0, which optimizes the balance between antiseptic effectiveness and skin compatibility. This parameter control ensures the agent remains effective while minimizing skin sensitivity issues.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a humectant with a specific distribution coefficient range that evaporates or degrades after serving its purpose of preventing skin sensitivity and maintaining ink stability, leaving no harmful residues on the printed surface.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If glycerin ether compound with high distribution coefficient is used, then antiseptic properties are retained, but ink stability at low temperature deteriorates

Engineering Contradiction:
Improveantiseptic propertiesVSAvoidink stability at low temperature
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the distribution coefficient parameter of the glycerin ether compound to a specific range (0.8 to 3.0), which balances the conflicting requirements: high enough to retain antiseptic properties, but low enough to maintain ink stability at low temperatures and prevent premature separation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If antiseptic agent concentration is increased to improve antiseptic performance, then microscopic organism propagation is prevented, but concentration on printed surface increases causing skin sensitivity

Engineering Contradiction:
Improveantiseptic performanceVSAvoidconcentration on printed surface
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent controls the distribution coefficient parameter to ensure the antiseptic agent remains predominantly in the bulk liquid phase rather than concentrating on the printed surface, achieving effective antiseptic performance while minimizing surface concentration that could cause skin sensitivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a humectant with specific distribution coefficient properties that acts as an intermediary substance, regulating the behavior of the antiseptic agent to prevent its concentration on the printed surface while maintaining its effectiveness in the ink composition.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If conventional solvents are used to maintain ink stability, then ink discharge stability is improved, but antiseptic performance is compromised

Engineering Contradiction:
Improveink stabilityVSAvoidantiseptic performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent creates a composite liquid composition system combining water, glycerin ester, and glycerin ether compound with specific distribution coefficients, where the synergistic interaction of components achieves both ink stability and antiseptic performance simultaneously.

Inventive Principle:
Principle #40Composite materials

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 solution provides a safe, effective antiseptic ink composition that prevents skin sensitivity and ensures stable ink discharge without nozzle clogging, while maintaining antibacterial and antifungal properties.

Implementation Method 1

a first solvent that is glycerin ester having a distribution coefficient of water-octanol which is in a range of 0.8 to 3.0; a second solvent that is an organic solvent having a distribution coefficient of water-octanol which is in a range of −1.0 to 1.0

Methodology Applied
Scientific EffectDistribution coefficient (water-octanol):

Implementation Method 2

the antiseptic and antifungal agent has biocidal activity, and thus, in a case where a label printing and a textile printing are performed by using the ink containing the antiseptic and antifungal agent

Methodology Applied
Scientific EffectAntiseptic and antifungal activity:

Implementation Method 3

the concentration of the antiseptic agent on the printed surface is likely to be high, and in the case of performing label printing and textile printing, the ink easily comes into contact with the skin when handling the printed matter, and thus, for the purpose of the above operations, there is a risk of allergic contact dermatitis being caused due to skin sensitivity

Methodology Applied
Scientific EffectSkin sensitivity mechanism:

Data Source

PatentUS9708500B2Liquid composition, pigment dispersion liquid, and aqueous ink composition for ink jet recording
Publication Date: 2017.07.18 SEIKO EPSON CORP

AI summary

Provided is a liquid composition containing a first solvent that is a glycerin ester having a distribution coefficient of water-octanol which is in a range of 0.8 to 3.0; a second solvent that is an organic solvent having a distribution coefficient of water-octanol which is in a range of −1.0 to 1.0; water; and a coloring material, in which a content of the first solvent is in a range of 0.005 mass % to 0.5 mass %, and a content of the second solvent is in a range of 0.5 mass % to 15 mass %.