Polymeric Dispersant for Pigment Ink Colloidal Stability
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Solution Overview
Problem
Pigment inks, particularly those containing C.I. Pigment Yellow 74 and 155, face challenges in achieving stable submicron particle sizes and colloidal stability, leading to agglomeration, flocculation, and poor fastness properties in ink jet printing, which affects their performance and adoption.
Innovation Solution
A polymeric dispersant is developed through copolymerizing benzyl (meth)acrylate and propylene glycol (meth)acrylate, with a weight ratio greater than 10:1, which effectively stabilizes the dispersion of these pigments, reducing milling times and enhancing colloidal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dispersants are used for C.I. Pigment Yellow 74 and 155, then the pigments can be dispersed, but the milling time is substantially longer and energy consumption is higher
Solution Approach 1:
The patent changes the chemical composition parameters of the dispersant by specifying a copolymer with at least 80 mol% of component (a) and at most 20 mol% of component (b), where component (a) is a (meth)acrylate monomer and component (b) is a carboxylic acid group-containing monomer. This specific compositional parameter optimization enables faster milling and reduced energy consumption for dispersing C.I. Pigment Yellow 74 and 155
2Stability of the object's composition
If C.I. Pigment Yellow 74 and 155 are dispersed to submicron particle sizes, then colloidal stability is improved, but the pigments tend to agglomerate and flocculate during storage and printing
Solution Approach 1:
The patent creates a composite dispersant system combining two different monomer components with specific functional groups - component (a) providing steric stabilization and component (b) providing electrostatic stabilization. This composite approach at the molecular level gives the dispersant dual mechanisms for preventing both agglomeration and flocculation, ensuring long-term colloidal stability of submicron pigment particles
Solution Approach 2:
The patent optimizes the molar ratio parameter between component (a) and component (b) in the copolymer, specifying at least 80:20 and preferably at least 90:10. This parameter optimization ensures the dispersant has sufficient steric stabilization from component (a) while maintaining adequate electrostatic stabilization from component (b), preventing both agglomeration and flocculation
3Productivity
If faster milling is achieved with optimized dispersants, then submicron particle sizes are obtained quicker, but the dispersant composition must be precisely controlled
Solution Approach 1:
The patent establishes specific parameter ranges for the copolymer composition (at least 80 mol% component (a) and at most 20 mol% component (b)), which optimizes the balance between milling efficiency and colloidal stability. These parameter specifications enable faster milling while maintaining straightforward compositional control through clear numerical boundaries
Data Source
AI summary
A polymeric dispersant obtained or obtainable by copolymerising a monomer composition comprising at least the components: i)benzyl (meth)acrylate; ii)propylene glycol (meth)acrylate; wherein the weight ratio of component i) to component ii) is greater than 10:1.