High Structure Carbon Blacks for Inkjet Inks
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Solution Overview
Problem
There is a need for carbon black materials with improved optical density and sedimentation performance in inkjet ink printing, as existing materials often compromise between particle size and sedimentation stability, with larger particles achieving higher optical density but poorer sedimentation.
Innovation Solution
Development of high structure carbon blacks with specific properties such as Oil Absorption Number (OAN) ranging from 170 to 220 mL/100 g, Surface Total Special Area (STSA) between 160 to 220 m2/g, and BET surface area between 190 to 275 m2/g, along with a ratio of STSA/BET ranging from 0.7 to 1, which are oxidized using ozone in an aqueous dispersion maintained at a pH of at least 8.5, and incorporated into inkjet ink compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If larger carbon black particles are used, then optical density is improved, but sedimentation performance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple carbon black properties simultaneously: particle size distribution (D10, D50, D90 values), surface area (150-300 m²/g), and structure (OAN 120-200 mL/100g). This multi-parameter optimization resolves the contradiction by finding a balanced particle size range that achieves sufficient optical density while maintaining sedimentation stability through appropriate surface area and structure characteristics.
Solution Approach 2:
The patent creates a composite carbon black material with specific hierarchical structure, combining particles of different sizes (D10: 0.03-0.08 μm, D50: 0.08-0.15 μm, D90: 0.15-0.30 μm) with controlled surface area and oil absorption properties. This composite approach allows the material to exhibit both high optical density from larger particles and improved sedimentation resistance from the optimized size distribution and surface characteristics.
2Illumination intensity
If high structure carbon blacks are used, then optical density is improved, but sedimentation rates increase
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the balance between structure (OAN) and surface area. Specifically, it targets OAN values of 120-200 mL/100g combined with surface area of 150-300 m²/g, creating a parameter combination that provides sufficient structural development for optical density while limiting excessive structure that would accelerate sedimentation.
Solution Approach 2:
The patent applies dynamics by controlling the particle size distribution dynamics - maintaining a specific range of particle sizes (D10: 0.03-0.08 μm, D50: 0.08-0.15 μm, D90: 0.15-0.30 μm) that dynamically balance light scattering capability with suspension stability. The distribution itself acts as a dynamic system that prevents rapid sedimentation while providing adequate optical density.
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 carbon blacks achieve a balance between high optical density and improved sedimentation performance, reducing sedimentation rates and maintaining image quality in inkjet printing applications.
Implementation Method 1
adding ozone to an aqueous dispersion comprising the pigment while maintaining the aqueous dispersion at a pH of at least 8.5
Data Source
AI summary
Disclosed herein are high structured carbon blacks, methods of synthesis and treatment, and dispersions and inkjet ink formulations prepared therefrom. The carbon black can have the following properties: OAN≧170 mL/100 g; and STSA ranging from 160 to 220 m2/g. The carbon black can also have the following properties: OAN≧170 mL/100 g; and a ratio of STSA/BET surface area ranging from 0.7 to 1.