Ink Composition with Polyurethane Resin for Scratch Resistance
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Solution Overview
Problem
Inks containing self-dispersing pigments with phosphonate groups offer high color development but compromise scratch resistance, and existing solutions that add polyurethane resin particles do not adequately address both requirements.
Innovation Solution
An ink composition combining phosphonate-type self-dispersing pigments with polyurethane resin particles and a specific surfactant, where the polyurethane resin particles have a particular anionic functional group content and volume average particle size, and the surfactant is added at a specific mass ratio to prevent hydrophilization of the recording medium surface, ensuring the ink stays on the surface for improved color development and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphonate-type self-dispersing pigments are used in ink, then color development is improved, but scratch resistance deteriorates
Solution Approach 1:
The patent combines phosphonate-type self-dispersing pigments with polyurethane resin particles having specific anionic functional group content (0.1-0.5 mmol/g) and controlled particle size (10-50 nm) to create a composite ink formulation. This composite approach allows the pigment to provide color development while the resin matrix provides scratch resistance, resolving the contradiction between these two properties.
Solution Approach 2:
The patent optimizes specific parameters including the anionic functional group content of polyurethane resin particles (0.1-0.5 mmol/g), particle size (10-50 nm), and surfactant mass ratio (0.05-1.0 relative to resin particles). By precisely controlling these parameters, the ink achieves both high color development and scratch resistance that cannot be obtained by simply mixing components without parameter optimization.
2Strength
If polyurethane resin particles are added to improve scratch resistance, then scratch resistance is improved, but color development deteriorates
Solution Approach 1:
The patent specifies narrow ranges for polyurethane resin particle parameters (anionic functional group content: 0.1-0.5 mmol/g, particle size: 10-50 nm) to maintain color development while achieving scratch resistance. Outside these ranges, color development deteriorates, indicating precise parameter control is essential to avoid this contradiction.
Solution Approach 2:
The patent creates local quality differences by having polyurethane resin particles with specific anionic functional groups interact differently with phosphonate-type pigments. The resin provides protective coverage where needed while maintaining pigment visibility and color properties in other areas, allowing simultaneous achievement of scratch resistance and color development.
3Stability of the object's composition
If surfactant is added to improve ink dispersibility, then dispersibility is improved, but recording medium surface hydrophilization occurs causing ink permeation
Solution Approach 1:
The patent optimizes surfactant concentration and mass ratio relative to polyurethane resin particles (0.05-1.0) to achieve adequate ink dispersibility without excessive surface hydrophilization. By controlling this parameter within a specific range, the ink maintains stability while preventing unwanted permeation into the recording medium.
Solution Approach 2:
The polyurethane resin particles act as an intermediary between the surfactant and the recording medium surface. The resin particles with specific anionic functional groups moderate the surfactant's interaction with the medium, providing dispersibility benefits while the resin itself forms a barrier that prevents excessive hydrophilization and ink permeation.
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 achieves both high color development and high scratch resistance through a synergistic effect of the components, preventing ink permeation into the recording medium and maintaining pigment near the surface, thus enhancing image quality.
Implementation Method 1
an ink containing a phosphonate-type self-dispersing pigment and polyurethane resin particles
Implementation Method 2
the surfactant is added at a specific mass ratio to prevent hydrophilization of the recording medium surface
Data Source
Figure 1~2
AI summary
An ink containing a self-dispersing pigment, polyurethane resin particles, a surfactant, and water, wherein the self-dispersing pigment is a pigment having a phosphonate group bonded directly or via another atomic group to the surface of the pigment, wherein the polyurethane resin particles have an anionic functional group content of 0.1 mmol/g or more and 0.4 mmol/g or less on the surfaces of the polyurethane resin particles and have a volume average particle size of 10.0 nm or more and 50.0 nm or less, and the surfactant includes a surfactant represented by a general formula (1), wherein the amount of the surfactant represented by the general formula (1) is 0.05 times or more and 1.00 times or less the amount of the polyurethane resin particles.