Bio-Based Polymeric Dispersant for Stable Aqueous Pigment Inks
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Solution Overview
Problem
Conventional aqueous inkjet inks using pigment dispersions struggle to achieve images with excellent adhesiveness and durability, such as rub resistance, and are not environmentally friendly due to the use of polymeric dispersants synthesized from petroleum materials, limiting their application on biodegradable printing substrates.
Innovation Solution
An aqueous pigment dispersion using a polymeric dispersant composed of (meth)acrylic acid and (meth)acrylate derived from biological materials, with specific molecular weight and polydispersity, neutralized with alkali, to stabilize pigment dispersion and enhance image durability, glossiness, and adhesiveness on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional polymeric dispersants synthesized from petroleum materials are used, then pigment dispersion is achieved, but environmental friendliness deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the dispersant by using polymers with specific acid values (30-250 mgKOH/g) and molecular weights (1,000-30,000), where at least part of carboxy groups are neutralized with alkali. This parameter optimization enables effective pigment dispersion while using environmentally conscious materials.
Solution Approach 2:
The invention uses composite polymer structures comprising constituent unit (i) from (meth)acrylic acid/itaconic acid and constituent unit (ii) from biological material-derived (meth)acrylates. This composite approach combines the dispersing capability of carboxylic acid groups with the environmental benefits of bio-based materials.
2Reliability
If aqueous inkjet inks containing pigment are used, then durability is improved, but adhesiveness deteriorates
Solution Approach 1:
The invention optimizes the acid value parameter of the polymeric dispersant to 30-250 mgKOH/g and molecular weight to 1,000-30,000, with polydispersity index of 2.5 or less. These parameter changes enable the dispersant to provide both durability through stable pigment suspension and adhesiveness through controlled interaction with substrates.
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 provides an environmentally conscious aqueous inkjet ink capable of recording images with excellent durability, glossiness, and adhesiveness on diverse substrates, including biodegradable materials, while maintaining high dispersion stability.
Implementation Method 1
a polymeric dispersant that disperses the pigment... having a number average molecular weight of 1,000 to 30,000, and having a polydispersity index of 2.5 or less
Implementation Method 2
at least part of carboxy groups are neutralized with an alkali... having an acid value of 30 to 250 mgKOH/g
Implementation Method 3
at least part of carboxy groups are neutralized with an alkali
Data Source
AI summary
There is provided an aqueous pigment dispersion that makes it possible to prepare an environmentally conscious aqueous inkjet ink in which a pigment is finely dispersed in a stable manner and at a high level and which is capable of recording an image having excellent durability, glossiness, color developability, and adhesiveness to various printing substrates. The aqueous pigment dispersion is an aqueous pigment dispersion containing a pigment, water, a water-soluble organic solvent, and a polymeric dispersant that disperses the pigment, wherein the polymeric dispersant is a polymer including a constitutional unit (i) derived from at least one of (meth)acrylic acid and itaconic acid, and a constituent unit (ii) derived from a (meth)acrylate derived from biological material, such as ethyl (meth)acrylate, having an acid value of 30 to 250 mgKOH/g, having a number average molecular weight of 1,000 to 30,000, and having a polydispersity index (weight average molecular weight/number average molecular weight) of 2.5 or less, wherein the content of the constituent unit (ii) is 50% by mass or more, and at least part of carboxy groups are neutralized with an alkali.