White Ink Formulation for Low Smoothness Substrates
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Solution Overview
Problem
Existing white inks struggle to achieve target luminosity on substrates with low smoothness due to permeation issues with hollow resin particles and acrylic silicone resins, leading to inadequate image quality.
Innovation Solution
A white ink formulation incorporating hollow resin particles, an organic solvent, and an acrylic silicone resin with a resin solubility parameter difference of 1 to 3 (cal/cm^3)0.5, where the acrylic silicone resin has a smaller solubility parameter than the hollow resin particle, preventing permeation into the substrate and achieving desired luminosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If hollow resin particles are used as coloring material in white ink, then white images can be obtained through refractive index difference, but the hollow resin particles permeate into substrates with low smoothness, failing to achieve target luminosity
Solution Approach 1:
The patent introduces acrylic silicone resin as an intermediary binding agent that adheres to both the hollow resin particles and the substrate. This mediator prevents the hollow resin particles from permeating into the substrate while maintaining their light-scattering function, thus achieving both luminosity and reliable substrate fixation.
Solution Approach 2:
The patent creates a composite ink formulation combining hollow resin particles (for luminosity) with acrylic silicone resin (for adhesion and substrate interaction). This composite structure allows the hollow particles to remain on the substrate surface rather than permeating in, achieving both high luminosity and reliable fixation.
2Reliability
If acrylic silicone resin is added to prevent hollow resin particle permeation, then substrate fixation improves, but the ink formulation becomes more complex and harder to control
Solution Approach 1:
The patent optimizes specific parameters of the acrylic silicone resin, including its solubility parameter (within 1-3 cal/cm³ of the hollow resin particle), glass transition temperature (20°C or lower), and molecular weight. By controlling these parameters, the formulation achieves effective substrate fixation while maintaining manageable complexity through defined specification ranges.
3Ease of operation
If polyurethane resin with glass transition temperature of 20°C or lower is used, then aqueous white ink can be formulated, but the resin solubility parameter mismatch causes permeation issues on low smoothness substrates
Solution Approach 1:
The patent changes the resin type from polyurethane to acrylic silicone resin, optimizing the solubility parameter to be within 1-3 cal/cm³ of the hollow resin particle. This parameter optimization prevents permeation on low smoothness substrates while maintaining aqueous formulation ease of use, thus improving image quality without sacrificing formulation simplicity.
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 a target luminosity of L* or higher at an attached amount of 2.1 mg/cm^2 on substrates with smoothness of 120 seconds or less, ensuring high image quality and substrate fixation.
Implementation Method 1
the resin solubility parameter of the acrylic silicone resin is smaller than that of the hollow resin particle
Implementation Method 2
Such a hollow resin particle demonstrates white utilizing the difference of refractive index between the inner layer and the outer crust resin of the hollow resin particle
Data Source
AI summary
A white ink includes a hollow resin particle, an organic solvent, an acrylic silicone resin, and water, wherein the acrylic silicone resin has a resin solubility parameter smaller than that of the hollow resin particle.