Polyurethane Binder Dispersion for Inkjet Decap Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current inkjet printing technologies face challenges with polyurethane-based inks, as high concentrations can lead to poor decap performance, affecting nozzle health and print reliability due to clogging and viscosity issues.
Innovation Solution
Inkjet inks incorporating a specific polyurethane binder with a polyol having two hydroxyl groups at one end and none at the other, forming a comb-like structure, along with other components like sulfonate or sulfonic acid and poly(ethylene glycol) homopolymers, improve decap performance and print reliability by maintaining low viscosity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high concentrations of polyurethane binder are used in inkjet inks to improve print durability and scratch resistance, then print quality and durability are improved, but decap performance deteriorates leading to nozzle clogging and poor print reliability
Solution Approach 1:
The patent changes the chemical structure parameters of the polyol component, specifically using a polyol with hydroxyl groups at both ends (diol) rather than conventional mono-hydroxyl polyols. This structural parameter change enables the formation of a comb-like polyurethane backbone with pendant groups, which fundamentally alters the ink's decap performance while maintaining print durability at high binder loadings
Solution Approach 2:
The patent creates a composite polyurethane structure combining a comb-like backbone formed from diol-based polyol with pendant groups from additional polyol components. This composite structure integrates the benefits of high binder loading for durability with improved decap performance, resolving the contradiction between print strength and reliability
2Manufacturing precision
If high binder loadings are used to achieve superior print quality and optical density, then print quality is improved, but viscosity increases causing jetting performance and nozzle health issues
Solution Approach 1:
The patent changes the molecular architecture parameters of the polyurethane binder by using diol-based polyols to create a comb-like structure with pendant groups. This structural change allows the ink to maintain lower viscosity even at high binder loadings (greater than 1% and up to 10% or more), enabling superior print quality without the harmful viscosity effects that normally accompany high concentrations
3Ease of manufacture
If conventional polyols with hydroxyl groups at both ends are used to form polyurethane backbone, then polymerization is simplified, but decap performance and nozzle health deteriorate
Solution Approach 1:
The patent inverts the conventional approach by using a polyol with hydroxyl groups at both ends (diol) to form the backbone, rather than using mono-hydroxyl polyols. This inversion creates a comb-like structure where the diol forms the main chain and additional polyol components become pendant groups, fundamentally improving decap performance and nozzle health while maintaining manufacturing simplicity
Data Source
AI summary
A binder dispersion includes water and polyurethane. The polyurethane is formed from polyisocyanate; polyol having two hydroxyl (OH) groups at one chain end, no OH groups at an opposed chain end, and a number average molecular weight (Mn) ranging from ˜500-˜5,000; an alcohol, diol or amine having a Mn<500; and one of i) a carboxylic acid; ii) a sulfonate or sulfonic acid having one amino group; iii) i and ii; iv) i and a homopolymer or copolymer of poly(ethylene glycol) (PEG) having one or two OH or amino groups at one chain end; v) ii and a homopolymer or copolymer of PEG having one or two OH or amino groups at one chain end; or vi) i, ii, and a homopolymer or copolymer of PEG having one or two OH or amino groups at one chain end.