Core-Shell Pigment Particles for Opacity
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Solution Overview
Problem
The extraction and manufacturing of titanium dioxide, a primary white pigment, are energy-intensive and environmentally impactful, and it faces challenges in dispersion and stability, especially in applications like inkjet inks due to its large size and high density, while alternative hollow polymer particles are mechanically fragile and ineffective under high humidity.
Innovation Solution
Development of white pigment compositions comprising core-shell particles with a polymer core and silica shell, attached via covalent bonds or non-covalent interactions, which exhibit excellent opacifying properties and can be used in inkjet printing without the need for additional surfactants or stabilizers, produced through simple mixing under ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If titanium dioxide is used as white pigment, then high refractive index and high opacity are achieved, but energy intensive manufacturing and environmental impact occur
Solution Approach 1:
The patent uses composite core-shell particles combining polymer core with silica or metal oxide shell. This composite structure achieves high opacity comparable to titanium dioxide while using materials that can be processed with lower energy requirements and environmental impact.
Solution Approach 2:
The patent modifies particle parameters including size (300-700 nm diameter), shell thickness (50-200 nm), and refractive index matching through polymer composition selection. These parameter optimizations enable effective opacity with alternative materials that avoid titanium dioxide's manufacturing issues.
2Illumination intensity
If titanium dioxide is used as white pigment, then high opacity is achieved, but dispersion and stability problems occur due to large size and high density
Solution Approach 1:
The patent creates core-shell structure where the polymer core provides organic compatibility for good dispersion, while the inorganic shell provides opacity. This local differentiation of properties within the particle structure solves both dispersion and opacity requirements simultaneously.
Solution Approach 2:
The patent reduces particle size to 300-700 nm diameter with controlled shell thickness of 50-200 nm. This size reduction improves dispersion characteristics and stability while maintaining sufficient opacity through optimized light scattering at the smaller scale.
3Weight of stationary object
If hollow polymer particles are used as alternative white pigment, then lower density and better dispersion are achieved, but mechanical fragility and poor performance under high humidity occur
Solution Approach 1:
The patent combines polymer material with silica or metal oxide shell to create composite particles. The inorganic shell provides mechanical strength and humidity resistance while the polymer core maintains low density and good dispersion properties, solving both fragility and performance issues.
Solution Approach 2:
The patent uses a thin polymer shell (50-200 nm) over the core that provides protective functionality. This thin film structure protects the core from environmental damage while maintaining the overall particle flexibility and low density characteristics.
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 core-shell particles effectively make a black substrate appear white at low surface coverage, providing excellent opacifying properties and stability, reducing the environmental impact and energy requirements compared to traditional methods.
Implementation Method 1
The core-shell particles exhibit excellent opacifying properties and can be used in inkjet printing
Implementation Method 2
The core and the shell are attached via covalent bonds formed between hydroxyl-reactive functional groups of the polymer and hydroxyl groups of the silica
Data Source
AI summary
White pigment compositions are provided. In embodiments, a white pigment composition comprises water and core-shell particles, each core-shell particle comprising a core and a shell over the core, wherein one of the core and the shell comprises a polymer and the other of the core and shell comprises silica. The polymer comprises an aromatic group, a hydroxyl-reactive functional group, and a polar group; and the silica comprises a hydroxyl group. The core and the shell are attached via covalent bonds formed between hydroxyl-reactive functional groups of the polymer and hydroxyl groups of the silica. Methods of making and using the white pigment compositions are also provided.