Solid Ink Composition for Writing Tool Cap-Off Time

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Solution Overview

Problem

Existing writing instruments with water-based ink compositions face issues with cap-off time, requiring heating to dissolve solid ink and lacking stability, which affects performance and usability.

Innovation Solution

A solid ink composition using polyethylene glycol with a melting point above 20°C and a humectant like glycerin, allowing for dissolution in cold water and improving cap-off time without altering the ink's coloring properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If solid ink is used in water-based writing instruments, then storage stability is improved, but dissolution requires heating which complicates the process

Engineering Contradiction:
Improvestorage stabilityVSAvoiddissolution process
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the solid ink by incorporating specific humectants (glycerin, propylene glycol, or butylene glycol) alongside polyethylene glycol. This compositional parameter change enables the ink to dissolve in cold water without heating, while maintaining storage stability. The humectants modify the dissolution properties of the solid ink matrix, allowing water to penetrate and dissolve the ink components at room temperature.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If water-based ink is used, then ease of operation is improved, but cap-off time is reduced causing the ink to dry out

Engineering Contradiction:
Improveease of useVSAvoidcap-off time
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent creates a composite ink system combining polyethylene glycol (solid matrix), humectants (water retention agents), and water-based coloring agents. This composite structure provides both the ease of operation of water-based inks and extended cap-off time through the humectant components that retain moisture in the ink reservoir, preventing premature drying.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If solid ink composition is stabilized, then consistency is improved, but exudation phenomenon occurs

Engineering Contradiction:
ImproveconsistencyVSAvoidexudation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent adjusts the compositional parameters by selecting specific ratios of polyethylene glycol to humectants and controlling the water content (1-10%). This parameter optimization achieves a balance where the ink remains stable and consistent in storage without excessive exudation. The humectants regulate moisture distribution within the solid matrix, preventing both drying out and excessive exudation.

Inventive Principle:
Principle #35Parameter changes

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 solid ink composition provides enhanced stability and cap-off time, allowing for easy dilution with tap water and maintaining color consistency, extending the writing instrument's usability without drying out.

Implementation Method 1

The solid ink composition can be diluted and dispersed to an ink by simply adding cold water, and even only tap water, followed by brief manual agitation such as shaking the ink by hand

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

The cap-off time of a writing instrument containing the aforementioned ink can be substantially improved by adding specific humectants

Methodology Applied
Scientific EffectHumectancy:

Data Source

PatentUS20230242780A1Handheld writing tool having improved cap-off time
Publication Date: 2023.08.03 SOCIETE BIC SA

AI summary

The present disclosure relates to writing instruments which are charged or recharged with a water-based ink composition. The water-based ink composition may be prepared from solid ink compositions which may be diluted with water. The solid ink composition comprises a specific combination of polyethylene glycol, at least one coloring agent and a humectant.