Polyurethane Inkjet Additive for Water Fastness and Jetting
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Solution Overview
Problem
Existing inkjet inks face challenges in achieving good print quality and jettability, particularly in thermal inkjet printheads, where the addition of polymer additives can compromise optical density and nozzle longevity.
Innovation Solution
Incorporating polyurethane additives derived from alkoxy aromatic diols and diols substituted with ionic groups, which function as binders to enhance the water fastness of printed images without affecting jetting performance, in aqueous inkjet ink compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer additives are added to improve water fastness of printed images, then durability is improved, but jetting performance deteriorates
Solution Approach 1:
The patent modifies the chemical parameters of the polymer additive by using alkoxy aromatic diols with specific molecular weight ranges (200-2000 g/mol) and controlling the polyurethane structure to balance film formation and jetting properties. This parameter optimization allows the ink to achieve both water fastness and acceptable jetting performance in thermal printheads
Solution Approach 2:
The invention creates a composite ink formulation combining colorants, aqueous vehicle, and polyurethane additives derived from alkoxy aromatic diols. This composite approach integrates multiple functional components that work synergistically to provide both durability enhancement and maintained jetting performance
2Illumination intensity
If polymer additives are added to improve optical density, then print quality is improved, but nozzle longevity deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyurethane additive within a specific range (200-2000 g/mol) to achieve the right balance between optical density enhancement and nozzle compatibility. The controlled polymer size prevents nozzle clogging while maintaining print quality
3Reliability
If polyurethane additives are added to improve water fastness, then durability is improved, but color performance may be compromised
Solution Approach 1:
The patent applies local quality by using small amounts of specifically designed polyurethane additives (0.01-5 wt% of total ink formulation) that provide water fastness enhancement without overwhelming the colorant properties. The localized, controlled addition maintains color integrity while providing durability benefits
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 use of these polyurethane additives improves optical density and durability of printed images, maintaining jetting performance and stability across both piezo and thermal inkjet systems, while preventing ink removal from the substrate.
Implementation Method 1
the polyurethane which comprises an alkoxy aromatic diol is a first polyurethane additive distinct from any polymeric dispersant used for the colorant and can be described as functioning as a binder in the ink
Data Source
AI summary
The invention provides an ink for inkjet printing, comprising colorant and certain polyurethane ink additives which is derived from alkoxy aromatic diol derived from alkoxy aromatic diols which enhances fastness of the print towards highlighter and finger smudge without compromising jetting performance and storage stability of the ink. The inks may be jetted from both thermal and piezo ink jet systems.