Polymer Dispersant Pigment Dispersion for Stable Ink-Jet Jetting
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Solution Overview
Problem
Existing methods for producing pigment dispersions for ink jet inks do not adequately address the issue of dispersion stability, leading to instability in jetting stability and potential bleeding in image recording.
Innovation Solution
A method involving the production of a polymer dispersant with specific structural units and controlled neutralization and crosslinking steps to achieve a pigment dispersion with enhanced dispersion stability, resulting in stable ink jet inks and reduced bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer dispersants are used for pigment dispersion, then the production process is simple, but the dispersion stability is insufficient leading to jetting instability
Solution Approach 1:
The patent applies preliminary action by performing neutralization of the polymer dispersant before the dispersion step. The polymer dispersant is neutralized to adjust its electrostatic properties, which enhances pigment adsorption and dispersion stability. This preliminary treatment ensures that the dispersant is in the optimal state before contacting the pigment, thereby improving dispersion stability without requiring complex equipment modifications.
Solution Approach 2:
The patent employs parameter changes by adjusting the degree of neutralization of the polymer dispersant. By controlling the neutralization degree within a specific range (30-80%), the electrostatic charge and adsorption capacity of the dispersant are optimized. This parameter adjustment significantly improves pigment dispersion stability and prevents jetting instability without complicating the production process.
2Reliability
If conventional dispersion methods are used, then the process is straightforward, but jetting stability deteriorates over time
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight and structural composition of the polymer dispersant. The dispersant is designed with specific structural units including carboxyl groups and hydrophobic chains, with molecular weight and composition ratios controlled within defined ranges. These parameter optimizations ensure long-term jetting stability by preventing pigment aggregation and maintaining dispersion uniformity, while the manufacturing process remains relatively simple.
Solution Approach 2:
The patent employs composite materials by creating a polymer dispersant with multiple functional structural units combined in one molecule. The dispersant contains carboxyl groups for electrostatic interaction, hydrophobic chains for adsorption, and specific molecular weight characteristics. This composite structure provides superior jetting stability by simultaneously achieving strong pigment binding and stable dispersion, without requiring complex manufacturing procedures.
3Reliability
If insufficient dispersion stability is achieved, then production is easier, but bleeding occurs in image recording
Solution Approach 1:
The patent applies parameter changes by precisely controlling the structural parameters of the polymer dispersant, including the ratio of hydrophobic to hydrophilic segments, molecular weight distribution, and degree of neutralization. These parameter optimizations ensure that the dispersant achieves maximum adsorption capacity and steric hindrance effects, effectively preventing pigment aggregation and bleeding during image recording. The process complexity remains manageable through systematic parameter control rather than complex procedural steps.
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 method produces a pigment dispersion with improved dispersion stability, ensuring stable jetting and suppressed bleeding in image recording, thereby enhancing the quality of ink jet inks.
Implementation Method 1
a structural unit L derived from at least one selected from the group consisting of a (meth)acrylic acid alkyl ester containing an alkyl group having 10 or more carbon atoms and an α-olefin containing an alkyl group having 10 or more carbon atoms
Implementation Method 2
a structural unit A containing an acid group, in which a proportion of the structural unit L is 20% by mass or more
Implementation Method 3
a neutralization step of neutralizing a part of the acid group contained in the polymer dispersant N to obtain a polymer dispersant A having a degree of neutralization of less than 100%
Implementation Method 4
a crosslinking step of crosslinking the polymer dispersant B in the uncrosslinked dispersion after the acid addition step to obtain a polymer dispersant C
Data Source
AI summary
The method for producing a pigment dispersion that includes neutralizing a part of an acid group in a polymer dispersant which contains a (meth)acrylic acid ester unit containing an alkyl group having 10 or more carbon atoms and contains an acid group, dispersing a pigment with the neutralized polymer dispersant to obtain an uncrosslinked dispersion, adding an acid to the uncrosslinked dispersion, and then crosslinking the uncrosslinked dispersion, in which an acid value AV1 after the neutralization, an acid value AV2 after the crosslinking, a degree of neutralization ND1 after the neutralization, and a degree of neutralization ND2 after the acid addition in the polymer dispersant satisfy inequalities (1) and (2); and applications thereof are provided, in which the inequality (1) is 0.60≤AV1(ND1−ND2)/(AV1−AV2)≤2.00, and the inequality (2) is 0.30≤(1−ND1)/(ND1−ND2)≤5.00.