White Ink Formulation for High-Temperature Luminosity Stability
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Solution Overview
Problem
Hollow resin particles used in white ink are prone to crushing when exposed to organic solvents with similar solubility parameters, leading to a decrease in luminosity, especially when dried at higher temperatures, which affects the quality of the printed image.
Innovation Solution
The white ink formulation includes a combination of 1,2-propane diol, 1,3-propane diol, 1,2-butane diol, isoprene glycol, and oxetane compounds as organic solvents, along with an acrylic silicone-based resin and a surfactant, which maintains the luminosity of the dried film at 50 or greater even when dried at 90 degrees C, with a dynamic surface tension of 18-21 mN/m, reducing the crushing of hollow resin particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If hollow resin particles are used as white ink material, then luminosity is improved, but the particles are easily crushed when contacted with organic solvents having similar solubility parameters
Solution Approach 1:
The patent changes the solubility parameter of the organic solvent by selecting specific solvents (1,2-propane diol, 1,3-propane diol, 1,2-butane diol, 1,3-butane diol, isoprene glycol, or oxetane compounds) with solubility parameters significantly different from the crust resin. This parameter change prevents dissolution and crushing of the hollow resin particles while maintaining luminosity.
2Productivity
If hollow resin particles are dried at higher temperatures to improve drying speed, then productivity is improved, but luminosity deteriorates due to particle crushing
Solution Approach 1:
The patent applies beforehand cushioning by selecting organic solvents with solubility parameters significantly different from the crust resin before the drying process. This pre-protection prevents particle crushing during high-temperature drying, allowing faster drying without luminosity loss.
3Ease of operation
If organic solvents with solubility parameters close to crust resin are used, then ease of operation is improved, but the crust resin is dissolved and hollow resin particle is crushed
Solution Approach 1:
The patent converts the potential harm of solvent-resin interaction into a benefit by deliberately selecting solvents with solubility parameters significantly different from the crust resin. This prevents dissolution and maintains particle integrity, turning a potential compatibility issue into a protective mechanism.
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 formulation ensures a luminosity decrease ratio of 10% or less between films dried at 70 and 90 degrees C, maintaining image quality and stability, and improves fixability and discharging reliability.
Implementation Method 1
Such a hollow resin particle demonstrates white utilizing the difference of refractive index between the inner layer and the crust resin of the hollow resin particle
Implementation Method 2
When the hollow resin particle is brought into contact with an organic solvent having a solubility parameter (SP) close to the SP value of the crust resin of the hollow resin particle, the crust resin is dissolved therein
Data Source
Figure 1~2
AI summary
A white ink includes a hollow resin particle, one or more first organic solvents, an acrylic silicone-based resin, a surfactant; and water. The luminosity (L*) of each of a first dried film having a thickness of 2.2 - 2.8 µm prepared by drying the white ink at 70 degrees C and a second dried film having a thickness of 2.2 - 2.8 µm prepared by drying the white ink at 90 degrees C is 50 or greater and the decrease ratio of the luminosity (L*) of the second dried film to the first dried film is 10 percent or less.