Thermal Inkjet Ink Formulation for Adhesion and Decap Performance
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Solution Overview
Problem
Thermal inkjet inks face challenges such as low optical density, short shelf life, slow drying times, poor decap time, and poor adhesion on low surface energy substrates, which affect their performance in industrial printing applications.
Innovation Solution
A thermal inkjet ink formulation that includes a base solvent comprising short chain alcohols, a tackifier such as terpene phenolic resin, one or more cosolvents like esters or ketones, and a colorant, which together enhance optical density, adhesion, and decap performance on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slow-drying solvent or cosolvent is introduced to mitigate poor decap performance, then decap performance is improved, but drying time becomes too slow causing ink smearing and reduced throughput
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by using a specific blend of esters (methyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate) with controlled vapor pressures and boiling points. This parameter optimization allows the ink to maintain adequate decap performance while drying at acceptable speeds, resolving the contradiction between decap performance and drying speed.
Solution Approach 2:
The patent employs a composite solvent system combining multiple ester components with different volatility characteristics. This composite approach allows synergistic effects where the combined vapor pressure and drying characteristics of the ester mixture provide both decap performance and acceptable drying speed, avoiding the extremes of single-solvent systems.
2Reliability
If decap additives with low to moderate vapor pressure are added to improve decap performance, then decap performance is improved, but adhesion to difficult-to-print substrates deteriorates
Solution Approach 1:
The patent optimizes the vapor pressure parameters of the solvent blend to achieve a balance where decap performance is improved without compromising adhesion. The specific ester combination provides controlled evaporation rates that facilitate decap while maintaining sufficient solvent presence for adhesion promotion on difficult substrates.
Solution Approach 2:
The patent uses ester solvents that replicate the beneficial adhesion characteristics of traditional solvent systems while achieving decap performance through their controlled vapor pressure profiles, effectively copying the adhesion functionality without sacrificing decap performance.
3Strength
If terpene phenol resins are used as tackifiers to improve decap performance and adhesion, then adhesion is improved, but layout on polyolefin substrates deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by replacing terpene phenol resins with specific ester-based solvent combinations. This parameter change maintains adhesion performance through the controlled evaporation and wetting characteristics of the ester blend while eliminating the layout problems associated with terpene phenol resins on polyolefin substrates.
Solution Approach 2:
The patent uses volatile ester solvents that evaporate cleanly without leaving residues that would cause layout problems. These short-living solvent molecules provide the necessary adhesion promotion during printing and then evaporate, preventing the permanent adhesion issues that would result from non-volatile tackifier residues.
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 formulation achieves high optical density, improved adhesion and layout on difficult-to-print substrates, faster drying times, extended decap time, and enhanced intermittent printing performance, thereby addressing the limitations of existing thermal inkjet inks.
Implementation Method 1
thermal inkjet printing uses a small resistor to rapidly heat a thin layer of liquid ink. A fraction of the ink is vaporized to form an expanding bubble that ejects a drop of ink from the ink cartridge onto the substrate
Implementation Method 2
The thermal inkjet ink includes a base solvent that includes a short chain alcohol, a tackifier, one or more cosolvents, and a colorant
Implementation Method 3
one or more cosolvents like esters or ketones... faster drying times
Data Source
AI summary
A thermal inkjet ink for industrial printing applications includes a primary solvent that includes at least a short chain alcohol, a tackifier that includes a terpene phenolic resin, one or more cosolvents that include at least an ester or a ketone, and a colorant that includes a pigment, a dye, or a combination thereof. The thermal inkjet ink may optionally include other components including, but not limited to, additional tackifiers or resins, one or more surfactants, a lubricant, and a security taggant.