Low-Viscosity Pigmented Fluid for Capillary Applicators

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The application of watercolor paints via capillary systems is hindered by their high viscosities, making it difficult to use them in applicators with capillary systems, as they require low viscosities for effective application, and existing solutions do not adequately address the need for water-solubility and storage stability.

Innovation Solution

Aqueous, pigmented writing, marking, and drawing liquid with a viscosity of less than 40 mPas, containing an aqueous pigment preparation, a water-soluble binder, a dispersing wetting agent, sugar or sugar alcohol, and a base, which allows for improved migration behavior and watercolorability, preventing pigment penetration into the surface and ensuring storage stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If watercolor paints are used in capillary systems, then watercolor techniques can be achieved, but the high viscosity prevents sufficient application

Engineering Contradiction:
Improvewatercolor technique capabilityVSAvoidapplication capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent modifies the physical-chemical parameters of the writing fluid by using low-viscosity aqueous pigment preparations instead of traditional high-viscosity watercolor paints. The fluid viscosity is reduced to less than 40 mPas through careful selection of binder types (water-soluble resins and polymer dispersions) and formulation components, enabling the fluid to flow through capillary systems while retaining water-soluble properties that allow watercolor techniques.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the viscosity is reduced for capillary application, then application via capillary systems is enabled, but storage stability deteriorates due to sedimentation

Engineering Contradiction:
Improvecapillary application capabilityVSAvoidstorage stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent introduces dispersing wetting agents as intermediary substances that mediate between the pigment particles and the aqueous medium. These agents prevent pigment sedimentation even at low viscosities by providing steric and electrostatic stabilization. The dispersing agents create a stable colloidal suspension that maintains uniform pigment distribution during storage while enabling low-viscosity flow for capillary application.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The writing fluid is formulated as a composite material system combining aqueous pigment preparations with specific binders (water-soluble resins and polymer dispersions), dispersing wetting agents, and other additives. This composite structure provides both the low viscosity required for capillary flow and the storage stability needed to prevent sedimentation, as each component contributes specific functional properties that complement each other.

Inventive Principle:
Principle #40Composite materials

3Reliability

If pigments migrate into the substrate, then water-permanent effect is achieved, but watercolor solubility is lost

Engineering Contradiction:
Improvewater-permanenceVSAvoidwatercolor solubility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent carefully controls the migration parameters of pigments into the substrate by using low-viscosity fluids that spread differently on paper surfaces compared to traditional paints. The aqueous pigment preparations with controlled binder systems allow pigments to remain more surface-adherent rather than deeply penetrating, maintaining water-solubility characteristics. This parameter control enables subsequent water manipulation typical of watercolor techniques while still providing some fixation.

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

Enables application via capillary systems, allows for watercolor techniques such as correction and distribution with a damp brush, and maintains storage stability by preventing sedimentation and clogging, ensuring effective use over time.

Implementation Method 1

the writing, marking, and/or drawing fluid is drawn onto the shaft by means of adhesion forces due to the capillary effect, it can be transported from the storage area to the tip of the application element

Methodology Applied
Scientific EffectCapillary effect: Capillary Action

Implementation Method 2

the dispersing wetting agent is an aqueous solution of a modified polymer with pigment-affine groups

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentEP3613814B2Writing, marking and/or character liquid for capillary systems, in particular for applicators with a capillary system, and applicator
Publication Date: 2023.10.18 A W FABER CASTELL GMBH & CO
  • EP3613814B2 patent drawingFigure 1

AI summary

The invention relates to a writing, marking, and/or drawing fluid, in particular an aqueous, pigmented, and/or water-soluble writing, marking, and/or drawing fluid, for capillary systems, especially for application devices with a capillary system, having a viscosity of less than 40 mPas, in particular less than 10 mPas (Brookfield, 20 °C, cone plate CPE-40), comprising an aqueous pigment preparation, a binder, a base, and a dispersing wetting agent, wherein the dispersing wetting agent is an aqueous solution of a modified polymer with pigment-affine groups. The invention further relates to an application device in which such a writing, marking, or drawing fluid is used.