Aqueous Ink Polymer Matrix for Scratch Resistance
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Solution Overview
Problem
Conventional pigment inks for inkjet recording lack sufficient scratch resistance, leading to material being scraped off when images are touched with sharp objects, particularly in outdoor applications where high durability is required.
Innovation Solution
An aqueous ink formulation using a combination of two polymers: polymer A, a block copolymer with an acid value of 120 mgKOH/g to 180 mgKOH/g and an ethylene oxide group, and polymer B with an acid value of 150 mgKOH/g or less and a hydrogen bond parameter of 1.0 cal0.5/cm1.5 to 3.2 cal0.5/cm1.5, which enhances dispersion and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pigment ink is used to achieve weatherability, then the image has good weather resistance, but the scratch resistance is insufficient and coloring material is scraped off when touched with sharp objects
Solution Approach 1:
The patent uses a composite ink formulation combining pigment particles with specific polymer dispersants and binding agents. The polymer dispersant forms a protective matrix around pigment particles, creating a composite structure that enhances scratch resistance while maintaining weatherability. This composite approach allows the image to resist both mechanical scratching and environmental degradation.
Solution Approach 2:
The patent modifies the chemical parameters of the ink formulation by controlling the molecular weight, composition, and concentration of polymer dispersants and binding agents. By optimizing these parameters, the ink achieves high scratch resistance without compromising the dispersion stability of pigment particles or the overall weatherability of the image.
2Reliability
If a large amount of polymer dispersant is incorporated into the ink to improve scratch resistance, then the scratch resistance increases, but the dispersion stability of pigment and storage stability of ink are reduced
Solution Approach 1:
The patent optimizes the concentration and molecular weight parameters of polymer dispersants to achieve the minimum effective amount for scratch resistance while maintaining pigment dispersion stability. By precisely controlling these parameters, the ink formulation avoids excessive polymer that would compromise dispersion stability.
Solution Approach 2:
The patent creates local variations in polymer distribution around pigment particles, where the polymer forms a protective shell at the particle surface while maintaining uniform dispersion throughout the ink. This local quality approach ensures scratch resistance at the image level without compromising overall dispersion stability.
3Reliability
If a large amount of polymer dispersant is incorporated into the ink to improve scratch resistance, then the scratch resistance increases, but the ejection stability of ink is reduced
Solution Approach 1:
The patent adjusts the viscosity and surface tension parameters of the ink formulation by optimizing polymer dispersant concentration and molecular weight. These parameter changes enable the ink to maintain stable ejection characteristics in the inkjet system while still providing high scratch resistance in the formed image.
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 ink achieves high storage stability and scratch resistance, preventing material scraping even when images are touched with sharp objects, thus meeting the durability needs of outdoor applications.
Implementation Method 1
a block copolymer having an acid value of 120 mgKOH/g or more to 180 mgKOH/g or less and having an ethylene oxide group as a nonionic group
Implementation Method 2
the polymer B has an acid value of 150 mgKOH/g or less and a hydrogen bond parameter (δh) of the polymer obtained by solubility parameters of monomers constituting the polymers of 1.0 cal0.5/cm1.5 or more to 3.2 cal0.5/cm1.5 or less
Data Source
AI summary
Provided is an aqueous ink with high storage stability and scratch resistance at such a high level that the coloring material of an image is not scraped off even when lightly touched with a sharp product. The aqueous ink includes a water-insoluble coloring material and plural polymers. The plural polymers include a polymer A which relatively contributes to dispersion of the water-insoluble coloring material and a polymer B which does not relatively contribute to the dispersion of the water-insoluble coloring material compared to the polymer A. The polymer A includes a block copolymer having an acid value of 120 mgKOH/g to 180 mgKOH/g and having an ethylene oxide group as a nonionic group. The polymer B has an acid value of 150 mgKOH/g or less and a hydrogen bond parameter (δh) of the polymer obtained by solubility parameters of monomers constituting the polymer of 1.0 cal0.5/cm1.5 or more and 3.2 cal0.5/cm1.5 or less.