Inkjet Recording Liquid Curl Suppression via Solvent SP Value
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Solution Overview
Problem
Existing inkjet recording methods face challenges with curling issues on plain paper and general-purpose coated paper, as well as limitations in storage and jetting stability, particularly with the methods disclosed in JP-A No. 2004-209762, JP-A No. 2007-152873, and Japanese Patent No. 3,932,820.
Innovation Solution
An inkjet recording liquid comprising water, at least one colorant, and a water-soluble organic solvent with a solubility parameter (SP) value of 27.5 or less, used at a content of 70 mass % or more, along with specific molecular weight ranges and formulations to suppress curling and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a printing method using ink containing polyhydric alcohol and water-soluble amide compound is used, then curling is reduced, but the printing method is greatly restricted and cannot be practically used
Solution Approach 1:
The invention changes the chemical parameters of the ink by specifying a water-soluble organic solvent with SP value of 27.5 or less and molecular weight of 240 to 1400, replacing the conventional polyhydric alcohol and water-soluble amide compound formulation. This parameter change maintains curl suppression effectiveness while improving printing method adaptability and practical usability.
Solution Approach 2:
The invention creates a composite ink formulation by combining water, colorant, and specifically selected water-soluble organic solvent (Formula 1 compound) with controlled molecular weight and SP value. This composite material approach achieves both curl suppression and practical printing application without the severe restrictions of previous methods.
2Object-affected harmful factors
If water-based ink containing solvent with low polarity at 30% or more is used, then curl is suppressed, but ink jetting property deteriorates
Solution Approach 1:
The invention changes the polarity parameter by selecting a water-soluble organic solvent with SP value of 27.5 or less (more polar than conventional low-polarity solvents) while controlling molecular weight at 240 to 1400. This parameter optimization maintains effective curl suppression while preserving excellent ink jetting properties, resolving the contradiction between curl control and jetting performance.
3Manufacturing precision
If ink containing two or more polyoxyalkyleneglycol-n-alkyl ethers is used, then color bleed is reduced, but curling cannot be suppressed
Solution Approach 1:
The invention creates a new composite ink formulation by replacing polyoxyalkyleneglycol-n-alkyl ethers with a specifically designed water-soluble organic solvent (Formula 1 compound) having controlled molecular weight (240-1400) and SP value (≤27.5). This composite material substitution simultaneously achieves both color bleed reduction and effective curling suppression, which were not achievable with the previous additive-based approach.
Data Source
AI summary
An inkjet recording liquid includes: water; at least one colorant; and a water-soluble organic solvent having an SP (solubility parameter) value of 27.5 or less at a content of 70 mass % or more with respect to the total amount of water-soluble organic solvent, wherein the water-soluble organic solvent having an SP value of 27.5 or less includes at least one water-soluble organic solvent having a molecular weight of from 240 to 1400 and represented by the following Formula (1) at a content of 70 mass % or more with respect to the amount of the water-soluble organic solvent having an SP value of 27.5 or less.R-An-OH Formula (1)In Formula (1), R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a group derived from a sugar alcohol having 3 to 12 carbon atoms; each A independently represents an ethyleneoxy group or a propyleneoxy group; and n represents an integer of from 3 to 24.