Ink Composition Using Glyceryl Mono-alkyl Ether for Skin Safety
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Solution Overview
Problem
Aqueous ink compositions for ink jet recording often suffer from skin sensitivity issues due to high concentrations of antiseptic and antifungal agents, and stability problems at low temperatures, leading to potential allergic contact dermatitis and nozzle clogging.
Innovation Solution
A liquid composition comprising a first glyceryl mono-alkyl ether with a specific water-octanol distribution coefficient range, combined with a second organic solvent having a lower distribution coefficient, along with water and a coloring material, to provide antiseptic performance without biocidal agents and ensure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antiseptic and antifungal agents (e.g., 1,2-benzisothiazolin-3-one, Proxel XL2S, sodium benzoate) are added to aqueous ink composition to prevent microbial propagation, then antiseptic performance is improved, but skin sensitivity and allergic contact dermatitis occur due to high concentration on printed surface
Solution Approach 1:
The patent changes the chemical parameters by replacing conventional antiseptic agents with a specific organic compound having particular molecular structure characteristics (logP value between 0.5 and 2.0). This parameter change allows the ink to maintain antiseptic properties while reducing skin sensitivity, as the new compound achieves effective microbial inhibition at lower concentrations that do not cause allergic reactions when concentrated on printed surfaces.
Solution Approach 2:
The patent employs a readily degradable organic compound that serves its antiseptic function temporarily during storage and then breaks down or dissipates, preventing long-term accumulation on printed surfaces. This approach provides sufficient antiseptic protection during the ink's usable life while minimizing residual harmful effects on skin contact.
2Stability of the object's composition
If glycerin ether compound with high distribution coefficient of water-octanol is used as humectant, then water solubility is improved, but ink stability deteriorates at low temperature due to easy separation from liquid composition
Solution Approach 1:
The patent modifies the molecular structure parameters of the glycerin ether compound by controlling the carbon number and hydroxyl group configuration, achieving an optimal balance between water solubility and low-temperature stability. Specifically, the compound maintains sufficient hydrophilicity for water solubility while having a molecular structure that prevents crystallization and separation at low temperatures, thus resolving the contradiction between solubility and stability.
3Reliability
If glycerin ether compound with low distribution coefficient of water-octanol is used, then ink stability is improved, but antiseptic effect is lost
Solution Approach 1:
The patent identifies and applies a specific parameter range for the distribution coefficient of water-octanol that simultaneously provides both antiseptic effect and ink stability. By selecting organic compounds with logP values between 0.5 and 2.0, the invention achieves a dual benefit: sufficient hydrophobicity to exhibit antiseptic properties against microbes while maintaining adequate water solubility and low-temperature stability, thus resolving the contradiction between antiseptic effect and ink stability.
Data Source
AI summary
Provided is a liquid composition containing a first solvent that is a first glyceryl mono-alkyl ether having a distribution coefficient of water-octanol which is in a range of 0.9 to 2.6; a second solvent that is an organic solvent having a distribution coefficient of water-octanol which is equal to or greater than −1.0 and less than 0.9; 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 %.