Aqueous Ballpoint Ink Dispersion Stability
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Solution Overview
Problem
Existing aqueous ink compositions for ballpoint pens containing titanium oxide suffer from decreased ink discharging performance when the pen cap is left off for an extended period, due to volatilization of water and subsequent aggregation of titanium oxide particles.
Innovation Solution
The addition of non-tacky urethane particles with a specific average particle size (0.1 μm to 6 μm) to the ink composition helps maintain the dispersion stability of titanium oxide, preventing aggregation and ensuring consistent ink discharging performance even after prolonged exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap of a ballpoint pen containing titanium oxide ink is taken off for a certain period of time, then the ink can be used for writing, but the ink discharging performance gets decreased due to water volatilization and titanium oxide aggregation
Solution Approach 1:
The patent introduces a specific polymer compound as an intermediary substance that mediates between the titanium oxide particles and the aqueous medium. This polymer acts as a dispersant that maintains the separation of titanium oxide particles even when water volatilizes during prolonged cap-off periods, preventing aggregation and maintaining consistent ink discharging performance.
Solution Approach 2:
The patent modifies the chemical parameters of the ink composition by incorporating a polymer compound with specific molecular weight and functional group characteristics. This parameter change in the composition enables the system to maintain dispersion stability under varying environmental conditions (cap on/off cycles) without requiring frequent recalibration or additives.
2Ease of operation
If water is used as the main solvent in the ink composition, then the ink is safe and easy to handle, but water volatilization causes titanium oxide particles to aggregate over time
Solution Approach 1:
The patent creates a composite aqueous ink system that combines water (for safety and ease of handling) with a specifically designed polymer compound (for stability). This composite material approach allows the ink to maintain both the safety benefits of water-based formulation and the dispersion stability needed for reliable performance over time, even during prolonged cap-off periods.
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 use of non-tacky urethane particles in the ink composition significantly enhances the ink discharging performance by preventing the aggregation of titanium oxide particles, thus maintaining excellent writing quality over time.
Implementation Method 1
when urethane particles having a specific physical property are added to such an ink composition containing titanium oxide, the discharging performance is improved
Implementation Method 2
volatilization of water around the ball lowers dispersion performance of titanium oxide, leading to aggregation
Data Source
AI summary
An ink composition for an aqueous ballpoint pen may have excellent ink discharging performance even if a pen point is exposed for a long period of time. Such an ink composition may contain at least from 1 to 35 mass % of titanium oxide having an average particle size of greater than 0.1 um and smaller than or equal to 1 μm, and from 1 to 35 mass % of non-tacky urethane particles having an average particle size from 0.1 to 6 μm.