Oil-Based Ballpoint Pen Ink Viscosity and Leakage Control

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Solution Overview

Problem

Conventional oil-based ballpoint pen inks have high viscosity, leading to a heavy writing sensation and poor performance at low temperatures, with issues of ink leakage and line discontinuity due to variations in viscosity and the use of low molecular weight resins.

Innovation Solution

An ink composition with a viscosity of 300 to 3000 cps, comprising a polyvinylbutyral (PVB) resin, polyvinylpyrrolidone (PVP) resin, and a solvent mixture with a high boiling point primary solvent and low boiling point secondary solvent, which maintains stability and prevents ink leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If high molecular weight resin is used to reduce viscosity, then writing smoothness is improved, but ink leakage occurs during rapid writing

Engineering Contradiction:
Improvewriting smoothnessVSAvoidink leakage prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite binder resin system combining high molecular weight resin (providing viscosity control and writing smoothness) with low molecular weight resin (providing ink leakage prevention). This composite approach allows the ink composition to achieve both low viscosity for smooth writing and adequate binding strength to prevent leakage during rapid writing.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If low molecular weight resin is used to reduce viscosity, then ink flow is improved, but line discontinuity occurs during rapid writing

Engineering Contradiction:
Improveink flowVSAvoidline continuity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs a composite binder resin system where low molecular weight resin components provide excellent ink flow and wetting properties, while high molecular weight resin components ensure line continuity and prevent breakage during rapid writing. The synergistic combination resolves the contradiction between improved ink flow and maintained line continuity.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If viscosity is reduced for smooth writing, then writing sensation is improved, but ink leakage occurs

Engineering Contradiction:
Improvewriting sensationVSAvoidink leakage prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent optimizes the molecular weight parameters of the binder resin components, specifically using high molecular weight resin with a weight average molecular weight of 50,000 or more. This parameter change allows the ink to achieve low viscosity for smooth writing sensation while the high molecular weight resin provides sufficient binding strength to prevent ink leakage.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If conventional high viscosity ink is used, then ink leakage is prevented, but writing sensation becomes heavy and smoothness is lost

Engineering Contradiction:
Improveink leakage preventionVSAvoidwriting smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent fundamentally changes the viscosity parameter of the ink composition by using high molecular weight binder resin components, achieving low viscosity (300-3000 cps) for smooth writing sensation. The specific selection of high molecular weight resin ensures that even at low viscosity, the ink maintains adequate binding properties to prevent leakage.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2787047B1Ink composition for oil-based ballpoint pen
Publication Date: 2018.07.04 SUHAN

AI summary

Disclosed are an ink composition for oil-based ballpoint pens which exhibits soft writing sensation due to low viscosity of 300 to 3000 cps, enables writing even at low temperatures and thus exhibits superior stability, and is free of leakage (of ink), and an oil-based ballpoint pen using the same.