Ballpoint Pen Ink Emulsion for Wear and Stability
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Solution Overview
Problem
Conventional writing ink compositions face issues with pigment aggregation and non-uniform dispersion, leading to poor light resistance, ball seat wear, and compromised smooth writing performance, despite attempts to improve long-term stability and viscosity.
Innovation Solution
A writing ink composition is developed as a W/O type emulsion, where a water-based component with a pigment and thixotropy imparting agent is dispersed in an oil-based component, incorporating a pigment dispersant and lubricant to prevent aggregation and wear, while controlling viscosity and wettability to ensure smooth writing and long-term stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a pigment is dispersed in an oil-based ballpoint pen ink, then light resistance of writing is improved, but pigment settling or aggregation occurs with time causing ball seat wear
Solution Approach 1:
The ink is divided into two separate phases: an oil-based component containing the pigment and a water-based component containing the lubricant. These phases are kept distinct but compatible, allowing the pigment to remain suspended in the oil phase while the lubricant protects the ball seat in the water phase, preventing direct contact between pigment particles and the ball seat.
Solution Approach 2:
A surfactant is introduced as an intermediary substance that mediates between the oil-based and water-based components. The surfactant reduces interfacial tension between the two phases, preventing phase separation and ensuring stable dispersion of pigment particles while allowing the lubricant to effectively protect the ball seat.
2Reliability
If a pigment is dispersed in an oil-based component with water-based component containing lubricant, then ball seat wear is suppressed, but pigment aggregation and nonuniformity occur reducing long-term stability
Solution Approach 1:
The invention carefully controls the ratio of oil-based to water-based components, optimizing it to maintain pigment dispersion stability while ensuring adequate lubricant availability. The surfactant concentration is also precisely controlled to prevent both pigment aggregation and phase separation, achieving a balance between ball seat protection and long-term compositional stability.
3Reliability
If viscosity is increased to suppress ball seat wear, then wear is reduced, but smooth writing performance and writing density are degraded
Solution Approach 1:
Instead of increasing overall ink viscosity, the invention changes the composition by introducing a water-based component with lubricant that works synergistically with the oil-based component. This approach provides ball seat protection through lubrication rather than viscosity, maintaining smooth writing performance while suppressing wear.
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 composition achieves high light resistance, smooth writing performance, and long-term stability by preventing pigment settling and aggregation, maintaining ink viscosity, and preventing ink bleeding and droplets, thus enhancing writing density and clarity.
Implementation Method 1
The ink composition is provided with thixotropy by adding a thixotropy imparting agent to the water-based component, thereby being able to show a high ink viscosity when leaving the ballpoint pen at rest and a decreased ink viscosity when writing
Implementation Method 2
This ink composition can be prepared, as a W/O type emulsion ink where water droplets composed of a water-based component with a pigment dispersed therein are dispersed in a oil-based component
Implementation Method 3
Adding a pigment dispersant to the water-based component raises the dispersion of the pigment, whereby the pigment settling or aggregation occurring with time can be more sufficiently suppressed
Implementation Method 4
a water-based component containing water, polyhydric alcohol, a thixotropy imparting agent, a pigment dispersant and a pigment, the water-based component being dispersed in an oil-based component
Data Source
Figure 1
AI summary
The writing ink composition of the present invention includes: an oil-based component containing a polar solvent and a spinnability imparting agent; and a water-based component containing water, polyhydric alcohol, a thixotropy imparting agent and a pigment, the water-based component being dispersed in the above oil-based component.