Pre-treatment Composition for Water Fastness
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Solution Overview
Problem
Aqueous inkjet printing technologies face challenges with water sensitivity of prints due to the solubility of alkali soluble latex resins, leading to inferior water fastness, and existing acidic pre-treatment compositions are corrosive to printer materials.
Innovation Solution
A pre-treatment composition comprising an organic matrix with acids or acid anhydrides, which are non-corrosive and only activate upon contact with water, stabilizing the alkali soluble latex resin to improve water fastness without damaging printer materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acidic pre-treatment compositions with very low pH are used to improve water fastness of printed matter, then water fastness is improved, but the pre-treatment composition becomes corrosive towards printer materials including printheads
Solution Approach 1:
The patent changes the pH parameter of the pre-treatment composition from very low (highly acidic) to a higher range (6-9), reducing corrosiveness while maintaining water fastness improvement through alternative mechanisms involving basic compounds and metal salts
Solution Approach 2:
The patent introduces metal salts (aluminum, zinc, calcium, magnesium) as intermediary compounds that mediate between the pre-treatment composition and the printed matter, providing water fastness through metal-pigment interactions rather than through strong acidification, thus avoiding corrosion of printer materials
2Ease of operation
If alkali soluble latex resin is used in ink composition to improve jettability, then jettability is improved, but the printed matter becomes water sensitive with inferior water fastness
Solution Approach 1:
The patent applies pre-treatment to the print media before printing, where basic compounds and metal salts are deposited on the media surface in advance. This preliminary action creates a receptive surface that interacts with the alkali soluble latex resin during printing, enabling the resin to form water-resistant bonds without requiring the ink itself to be acidic
Solution Approach 2:
The patent converts the water sensitivity caused by alkali soluble latex resin into a benefit by using basic pre-treatment compounds that react with the resin to form water-resistant complexes. The same basic compounds that neutralize the resin's water solubility also promote adhesion and water fastness, turning the harmful water sensitivity into improved water resistance
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 solution enhances the water fastness of printed matter while being non-corrosive to printer components, allowing for improved print quality and ease of recycling by adjusting the pH of the ink composition.
Implementation Method 1
the acidic anhydride reacts with the water from the ink composition and in-situ forms an acidic pre-treatment primer on the receiving medium
Implementation Method 2
an aggregation agent for destabilizing and pinning pigment particles and/or for destabilizing of dispersed polymer particles (e.g. latex) in order to facilitate film formation
Data Source
AI summary
Disclosed is a substantially water-free pre-treatment composition having at least one of an acid or an acid anhydride in an organic matrix. Also disclosed is a kit of parts having the pre-treatment composition and an ink composition that has an intrinsic inferior water fastness when printed, where the ink contains a compound that is soluble in alkaline environment (ink as such) and insoluble in a neutral and/or acidic environment. Also disclosed is a printing method for improving the water fastness of a print made with an ink that has intrinsically low water fastness, by using a pre-treatment composition as disclosed.