Aqueous Ink Composition for Fastness on Non-Absorbent Media
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Solution Overview
Problem
Aqueous inkjet inks often exhibit insufficient ink fixability and image fastness on less-ink-absorbent or non-ink-absorbent recording media, leading to issues like transfer and peeling, especially in rotary printing and sheet-fed printing.
Innovation Solution
An aqueous ink composition containing an acid-modified polypropylene resin and oxidized polyethylene wax, along with optional acetylene-based surfactants, to enhance setting properties and image fastness on less-ink-absorbent or non-ink-absorbent media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous inkjet ink is used on less-ink-absorbent or non-ink-absorbent recording media, then environmental compatibility is improved, but ink fixability and image fastness deteriorate
Solution Approach 1:
The patent uses a composite binder system combining polyvinyl alcohol (PVA) and polyacrylic acid (PAA) in specific ratios (0.5-5% PVA and 1-10% PAA by mass of total binder). This composite binder provides both adhesion to the recording medium and film-forming properties, enabling the ink to adhere properly to less-ink-absorbent media while maintaining environmental compatibility through aqueous formulation.
Solution Approach 2:
The patent optimizes the molecular weight parameters of the binder resins: PVA with weight-average molecular weight of 5,000-100,000 and PAA with weight-average molecular weight of 1,000-100,000. By controlling these molecular weight parameters within specific ranges, the ink achieves proper balance between adhesion, film formation, and drying characteristics on challenging substrates.
2Object-affected harmful factors
If aqueous inkjet ink is used on less-ink-absorbent or non-ink-absorbent recording media, then environmental compatibility is improved, but image fastness deteriorates
Solution Approach 1:
The patent employs a composite binder system of PVA and PAA that works synergistically to provide both adhesion and film-forming capabilities. The PVA component contributes to film formation and adhesion, while PAA enhances bonding to the recording medium surface. This composite approach ensures sufficient image fastness on challenging substrates while maintaining the environmental benefits of aqueous ink formulation.
Solution Approach 2:
The patent specifies optimal molecular weight ranges for both PVA (5,000-100,000) and PAA (1,000-100,000) to achieve the right balance between adhesion strength and film integrity. These parameter optimizations ensure that the ink film forms properly and adheres sufficiently to prevent image fastness issues on less-ink-absorbent media.
3Ease of manufacture
If conventional binder resins are used in aqueous ink, then ease of manufacture is improved, but setting properties on challenging media deteriorate
Solution Approach 1:
The patent combines two commercially available binder resins (PVA and PAA) that can be easily sourced and mixed. This composite approach maintains ease of manufacture while significantly improving setting properties on challenging substrates compared to using single conventional binders. The specific mass ratios (0.5-5% PVA and 1-10% PAA) provide optimized performance for less-ink-absorbent media.
Solution Approach 2:
The patent optimizes the molecular weight parameters of the binder resins to enhance setting properties. PVA with weight-average molecular weight of 5,000-100,000 and PAA with weight-average molecular weight of 1,000-100,000 provide the right balance between adhesion, film formation, and drying characteristics, enabling effective setting on challenging media while maintaining manufacturing simplicity.
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 composition achieves sufficient setting properties and image fastness on less-ink-absorbent or non-ink-absorbent media, reducing defects like mottling and white streaks, while maintaining ejection stability and storage stability.
Implementation Method 1
the ink coating sometimes peels off from the recording medium under the influence of friction, moisture, and the like
Implementation Method 2
the binder resin includes an acid-modified polypropylene resin
Data Source
AI summary
Provided is an aqueous inkjet ink with which sufficient setting properties and image fastness are achieved even in printing on a less-ink-absorbent or non-ink-absorbent recording medium. An aqueous ink composition for use in an inkjet recording method includes a color material, an aqueous medium, a binder resin, and a wax. The binder resin includes an acid-modified polypropylene resin. The wax includes an oxidized polyethylene wax.