Polyurethane Inkjet Ink Dispersibility and Jetting
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Solution Overview
Problem
Inkjet ink compositions face challenges with nozzle clogging due to polymers that are not soluble in certain liquid media, leading to difficulties in printing and requiring improved print durability and reliability.
Innovation Solution
The development of inkjet ink compositions comprising at least one pigment and a polyurethane dispersion made from polypropylene glycol and diisocyanate, with a weight average molecular weight of no more than 80,000, where the polyurethane contains at least 70 wt % polypropylene glycol, enhancing dispersibility and print performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If emulsion polymers or latexes are used as dispersants to improve pigment dispersibility, then pigment dispersibility improves, but nozzle clogging occurs due to insolubility in liquid media
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer dispersant by incorporating soluble polymer components (such as polyvinyl alcohol, carboxymethyl cellulose, or starch derivatives) alongside emulsion polymer components. This parameter modification enables the dispersant to maintain both high pigment dispersibility and solubility in the liquid media, preventing nozzle clogging while improving pigment distribution.
Solution Approach 2:
The invention creates a composite polymer dispersant system that combines emulsion polymer components (for dispersibility) with soluble polymer components (for solubility). This composite material approach allows the dispersant to simultaneously achieve excellent pigment dispersion and remain soluble in the inkjet liquid media, resolving the contradiction between dispersibility and printing reliability.
2Duration of action of stationary object
If polymers are incorporated to improve print performance and dispersibility, then print durability improves, but jetting capability deteriorates due to viscosity and clogging
Solution Approach 1:
The patent optimizes the molecular weight and composition parameters of the polymer dispersant to balance print durability and jetting capability. By selecting specific soluble polymer components with appropriate molecular weights and incorporating them in controlled amounts, the formulation achieves sufficient viscosity for durable printing while maintaining low enough viscosity for effective jetting.
Solution Approach 2:
The invention applies different polymer components with specialized functions at different stages: soluble polymer components ensure easy jetting and nozzle flow during printing, while emulsion polymer components provide enhanced adhesion and durability on the printed surface. This local quality differentiation resolves the contradiction between jetting capability and print durability.
Data Source
AI summary
Disclosed herein are inkjet ink compositions comprising: at least one pigment and at least one polyurethane comprising: at least one polypropylene glycol, and at least one diisocyanate. The at least one polyurethane contains at least 70 wt % polypropylene glycol relative to the at least one polyurethane and has a weight average molecular weight (Mw) of no more than 80,000.