Aqueous Ink Pen Core Protection Against Dye Deposition
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Solution Overview
Problem
Existing writing instruments with aqueous ink compositions face issues such as dye deposition on the pen core, leading to ink discoloration and a hard writing touch, which affect the writing performance and feeling.
Innovation Solution
A writing instrument equipped with a pen core and an aqueous ink composition containing colored resin particles formed by polymerization of a monomer containing cyclohexyl (meth)acrylate, enclosing a basic dye, an oil-soluble dye, or an acid dye, and an anionic surfactant to prevent dye deposition and improve writing feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous ink composition containing colored resin particles is used, then writing performance is improved, but dye deposition occurs on the pen core over time
Solution Approach 1:
The patent introduces a specific surfactant as an intermediary substance between the colored resin particles and the pen core. This surfactant adsorbs onto the pen core surface, creating a barrier that prevents dye molecules from directly contacting and depositing on the pen core, thereby maintaining writing performance while eliminating dye deposition
Solution Approach 2:
The patent modifies the chemical composition parameters of the aqueous ink by carefully controlling the type and concentration of surfactant, along with specific pH and ionic strength parameters. These parameter changes alter the surface charge and interaction forces between ink components and the pen core, preventing dye deposition while maintaining stable colloidal dispersion
2Stability of the object's composition
If dye is enclosed in colored resin particles, then color stability is improved, but ink discoloration occurs due to dye deposition on the pen core
Solution Approach 1:
The surfactant acts as a protective intermediary layer on the pen core surface, preventing dye molecules that may be released from resin particles from contacting the pen core. This intermediary barrier maintains color stability by preventing the harmful interaction that causes ink discoloration
Solution Approach 2:
The patent applies surfactant treatment beforehand to the pen core surface, creating a protective cushion that anticipates and prevents potential dye deposition and subsequent discoloration issues before they occur during storage and use
3Ease of manufacture
If conventional ink composition is used, then manufacturing is simple, but writing feeling is hard and caught sensation occurs
Solution Approach 1:
The patent optimizes specific parameters of the aqueous ink composition including surfactant concentration (0.1-10 mass%), pH (6.0-8.0), and ionic strength, which fundamentally changes the ink's rheological properties and surface tension. These parameter adjustments create a smoother ink flow and better writing feeling while maintaining ease of manufacture through standard formulation techniques
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 solution effectively prevents dye deposition on the pen core, inhibits ink discoloration, and enhances writing feeling without impairing performance.
Implementation Method 1
To prevent ink discoloration caused by adsorption of a coloring material of an ink for a writing instrument on the pen tip
Implementation Method 2
the aqueous ink composition containing: colored resin particles colored with a dye, and an anionic surfactant
Data Source
Figure 1A~1N
Figure 2A~2J
Figure 3
AI summary
Object: Provided is a writing instrument capable of preventing dye deposition to a pen core and highly achieving both inhibition of ink discoloration due to the dye deposition and improved writing feeling without reducing writing performance. Solution Means: A writing instrument equipped with a pen core and loaded with a water-based ink composition, the water-based ink composition containing colored resin particles being formed by polymerization of a monomer comprising at least cyclohexyl (meth)acrylate and enclosing a basic dye, an oil-soluble dye or an acid dye, and containing an anionic surfactant.