Capillary Writing Fluid Resin Mixture for Waterproof Marking
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Solution Overview
Problem
Conventional writing, marking, and drawing fluids used in capillary writing instruments face issues such as low waterproofness, inadequate wetting on greasy surfaces, limited smudge resistance, and poor lightfastness, while high-viscosity fluids can only be applied through valve systems, and toxic solvents like xylene and toluene are used in industrial markers.
Innovation Solution
A writing fluid with a viscosity of less than 50 mPas, containing a resin mixture of adhesive and hard resins, fluorosurfactants, and polyethersiloxane copolymers, which improves adhesion, water resistance, and abrasion resistance, and can be applied via capillary systems, using solvents like ethyl acetate and ketones that are safer than aromatic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional writing fluids are used in capillary systems, then the fluid can be applied through capillary action, but the spreads show poor water resistance and are only splash-proof
Solution Approach 1:
The patent uses a composite resin system combining polyester resin (providing adhesion and flexibility) with acrylic resin (providing hardness and water resistance). This composite material approach allows the spread to achieve both capillary applicability and superior waterproofness that resists immersion and rain tests.
2Ease of operation
If conventional writing fluids are used, then the fluid can flow through capillary material, but the wetting on greasy or oily surfaces is inadequate
Solution Approach 1:
The patent introduces surfactants as intermediary substances that mediate between the aqueous-based capillary fluid and the hydrophobic greasy surfaces. These surfactants reduce surface tension and enable the fluid to wet and adhere to oily surfaces effectively while maintaining capillary flow properties.
3Reliability
If highly viscous pigmented liquids are used, then improved smudge resistance and water resistance can be achieved, but the liquids cannot be applied through conventional capillary systems
Solution Approach 1:
The patent carefully controls the viscosity parameter of the writing fluid to remain below 50 mPas at 20°C, ensuring capillary applicability. Simultaneously, the resin concentration and composition are optimized to provide sufficient smudge resistance and adhesion, achieving a balance between flow properties and performance characteristics.
4Reliability
If industrial markers with aromatic solvents are used, then good smudge resistance can be achieved, but toxicologically questionable solvents like xylene and toluene are used
Solution Approach 1:
The patent replaces toxic aromatic solvents with safer alternative solvents while compensating for any potential performance loss through optimized resin formulation. The acrylic-polyester resin system is specifically designed to work with these safer solvents, maintaining smudge resistance and adhesion properties without the health hazards of xylene or toluene.
5Ease of operation
If conventional writing fluids are used, then the fluid can be applied smoothly, but the light fastness of the spreads is very poor after UV exposure
Solution Approach 1:
The patent incorporates UV stabilizers and light-resistant pigment formulations into the writing fluid before application. These preventive measures are built into the fluid composition itself, providing inherent protection against UV degradation and ensuring long-term color stability and light fastness of the spreads.
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 fluid achieves improved adhesion, water resistance, and smudge resistance on various surfaces, including those with grease or oil, and exhibits excellent lightfastness, allowing reliable application through capillary systems without the need for toxic solvents.
Implementation Method 1
a reservoir for the writing, marking and/or drawing liquid made of a capillary material, for example made of polyester or polyolefin fibers, which is fluidly connected to an application element made of a likewise capillary material, for example a fiber or sintered tip, so that the writing, marking and/or drawing liquid can be transported from the storage to the tip of the application element due to adhesion forces or the capillary effect
Data Source
Figure 1
AI summary
The invention relates to a writing, marking and/or drawing fluid for writing instruments, in particular for capillary writing instruments, which has a viscosity of less than 50 mPas (Brookfield, 20 °C, cone plate CPE-40), containing a resin mixture dissolved in a solvent matrix comprising at least one solvent, wherein the resin mixture contains as a first resin an adhesive resin and as a second resin a hard resin.