Water-Based Ink Composition for Ballpoint Pens

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Solution Overview

Problem

Ink compositions for writing instruments that excel in drying properties tend to bleed easily on paper, making lines unclear.

Innovation Solution

A water-based ink composition for ballpoint pens comprising polyoxyethylene alkyl ether with an HLB value of 14 to 15 and an alkyl group of 8 to 10 carbon atoms, along with a phosphate ester, a water-soluble organic solvent, and colorants, which balances drying properties and bleed prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If ink composition is designed for excellent drying property, then drying speed is improved, but bleed resistance deteriorates

Engineering Contradiction:
Improvedrying timeVSAvoidbleed resistance
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the HLB value of polyoxyethylene alkyl ether within the specific range of 14 to 15, and limiting the alkyl group to 8-10 carbon atoms. This precise parameter optimization enables the surfactant to achieve the right balance between promoting rapid water evaporation (improving drying speed) and maintaining ink film integrity on paper (preventing bleed), thereby resolving the contradiction between drying property and bleed resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite ink composition system that integrates polyoxyethylene alkyl ether with specific HLB value (14-15) alongside other ink components including colorants, water-soluble organic solvents, and additives. This composite formulation creates synergistic effects where the specially selected surfactant works in conjunction with other components to achieve both fast drying and good bleed resistance, transforming the trade-off into a coordinated performance

Inventive Principle:
Principle #40Composite materials

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 forms lines with excellent drying properties and minimal bleed, ensuring clear and intended line thickness.

Implementation Method 1

a water-based ink composition for a ballpoint pen comprising a polyoxyethylene alkyl ether... wherein the HLB value of the polyoxyethylene alkyl ether is from 14 to 15

Methodology Applied
Scientific EffectSurfactant: Surfactant

Data Source

PatentEP2940084B1Water-based ink composition and water-based ballpoint pen
Publication Date: 2017.11.01 ZEBRA
  • EP2940084B1 patent drawingFigure 1
  • EP2940084B1 patent drawing

AI summary

The object of the present invention is to provide a water-based ink composition capable of forming depicted lines excellent in drying property and with little bleed and a water-based ballpoint pen using the same. The present invention provides a water-based ink composition including a polyoxyethylene alkyl ether, a water-soluble organic solvent, a colorant and water, wherein the HLB value of the polyoxyethylene alkyl ether is from 12 to 15, and wherein the polyoxyethylene alkyl ether has an alkyl group containing 8 to 12 carbon atoms.