ABA Block Copolymer Dispersant for Pigment Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The acidic dispersant in existing pigment dispersion compositions has insufficient dispersibility, requiring higher usage levels which can adversely affect the solubility of other additives, necessitating an acidic dispersant with improved dispersibility.
Innovation Solution
A block copolymer with an acid value of 30 to 250 mgKOH/g, comprising an ABA structure where the B block contains 40% or more of a vinyl monomer with an acid group, used as a dispersant to enhance pigment dispersion stability, formed through living radical polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of acidic dispersant is increased to improve dispersibility, then pigment dispersibility is improved, but the solubility of other additives is adversely affected
Solution Approach 1:
The dispersant is segmented into an A block (non-acidic, compatible with additives) and a B block (acidic, adsorbs to pigment). This segmentation allows the acidic functional groups to be localized in the B block, providing effective pigment dispersibility while the A block maintains compatibility with other additives, thus resolving the contradiction between dispersibility and additive solubility.
Solution Approach 2:
The acid groups are locally concentrated in the B block rather than being distributed throughout the entire dispersant molecule. This local quality approach allows the acidic regions to effectively interact with basic pigment surfaces for improved dispersibility, while the non-acidic A block regions maintain solubility compatibility with other additives in the composition.
2Reliability
If fine particles are used to exhibit sufficient performance, then pigment performance is improved, but viscosity increases making transport and storage difficult
Solution Approach 1:
The block copolymer dispersant acts as an intermediary between fine pigment particles and the dispersion medium. It adsorbs to the pigment surface through the acidic B block and extends into the dispersion medium through the non-acidic A block, providing steric stabilization and reducing interparticle interactions, thus maintaining low viscosity while enabling the use of fine particles for optimal performance.
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 block copolymer provides excellent dispersion stability and improved pigment dispersibility, preventing agglomeration and maintaining low viscosity, thus enhancing the usability and performance of pigment dispersion compositions.
Implementation Method 1
The dispersant has a structure including a part adsorbable to a pigment and a part having a high affinity for a dispersion medium
Implementation Method 2
an acidic part (acidic dispersant) is used for a pigment having a surface biased toward the basic side
Data Source
AI summary
Provided is a block copolymer with an acid group that, when used as a dispersant, can provide a dispersion composition having excellent dispersion stability, a dispersant containing the block copolymer, and a pigment dispersion composition using the dispersant. The block copolymer is an ABA block copolymer including an A block and a B block and has the feature that its acid value is 30 to 250 mgKOH/g and the B block contains a structural unit derived from a vinyl monomer with an acid group.