Coloring Tablet Composition for Soluble, Redispersible Water-Based Ink

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Solution Overview

Problem

Existing ink compositions for writing instruments face issues with solubility and limited color options, particularly in painting and calligraphic work materials, and solubility is affected by the generation of carbonic acid gas in ink for writing instruments.

Innovation Solution

A coloring tablet containing a colorant and a dispersing agent, such as hydroxide neutralization products of (meth)acrylic resins and polyoxyethylene-based surfactants, with a mass ratio of 0.5 to 10, and optionally reinforced with polyvinyl alcohol, is used to create a water-based ink composition with excellent solubility and redispersibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If colorants are used in powder form dissolved in water or liquid for ink, then the ink composition can be prepared, but the solubility is insufficient and the coloring material is limited

Engineering Contradiction:
ImprovesolubilityVSAvoidcoloring material options
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention uses composite colorant pellets comprising multiple components (coloring material, water-soluble resin, and optional carbonic acid gas-generating agents) instead of simple powder colorants. This composite structure enables both high solubility through the water-soluble resin matrix and versatility in coloring material selection (organic dyes, inorganic pigments, natural colorants)

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical state and dissolution mechanism by using pellets with controlled solubility parameters. The water-soluble resin content and molecular weight are optimized to achieve rapid dissolution, and optional carbonic acid gas generation is used to enhance disintegration and solubility through bubble formation

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If colorant pellets are reacted with mixed solvent at the time of use, then the ink is prepared, but the added amounts of other components are affected and the coloring material is limited to food dye

Engineering Contradiction:
Improveink preparation processVSAvoidcoloring material types
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention extracts the dissolution function from the ink formulation by incorporating water-soluble resin directly into the colorant pellet structure. This eliminates the need for separate resin addition and simplifies the ink preparation process while expanding coloring material options beyond food dyes to include industrial pigments and dyes

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If carbonate and organic acid are used in colorant pellet to generate carbonic acid gas for disintegration, then solubility is enhanced, but the added amounts of other components are affected

Engineering Contradiction:
ImprovesolubilityVSAvoidcomponent amounts
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention uses small amounts of carbonic acid gas-generating agents (carbonate and/or organic acid) as optional additives in the colorant pellet. These agents provide partial enhancement of solubility through bubble-induced disintegration, but are not required in excessive amounts, allowing flexible formulation with controlled component quantities

Inventive Principle:
Principle #16Partial or excessive action

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 provides a water-based ink composition with superior solubility and redispersibility, allowing for various colors and concealing abilities, suitable for use in conventional writing instruments.

Implementation Method 1

a water-based ink composition for a writing instrument, which is prepared by allowing the coloring tablet to dissolve or disperse in a liquid for ink that is a solvent

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

a coloring tablet having excellent solubility and redispersibility

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS12559637B2Coloring tablet and water-based ink composition for writing instrument using the same
Publication Date: 2026.02.24 MITSUBISHI PENCIL CO LTD

AI summary

A coloring tablet may have excellent solubility and redispersibility and a water-based ink composition for a writing instrument. Such a coloring tablet may contain at least a colorant and a dispersing agent. The dispersing agent may include a hydroxide neutralization product of an (meth)acrylic resin, a hydroxide neutralization product of a styrene-maleic acid copolymer resin, a polyoxyethylene-based surfactant, an alkyl condensed ring sulfonate, an amine ethylene oxide propylene oxide adduct, and/or a isobutylene-based polymer.