Nonspherical Silica Particles for Toner Fluidity
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Solution Overview
Problem
Existing silica particles used in toners, cosmetics, and abrasives often suffer from poor fluidity, attachment properties, and dispersibility due to their spherical shape and broad particle size distribution, leading to issues like uneven distribution and detachment when mixed with other particles.
Innovation Solution
Silica particles with a volume average particle diameter of 80-300 nm, a particle size distribution index of 1.10-1.40, an average circularity of 0.70-0.92, and a circularity distribution index of 1.05-1.50, and a proportion of primary particles with a circularity of 0.95 or more being 10% or less, are produced using a sol-gel method with controlled alkali catalyst and tetraalkoxysilane supply rates to achieve a nonspherical shape and improved dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silica particles have a spherical shape and broad particle size distribution, then production is easier, but fluidity and dispersibility deteriorate
Solution Approach 1:
The invention changes the particle size distribution parameter by controlling the sol-gel reaction conditions, specifically maintaining a particle size distribution index within 1.05-1.60 and limiting spherical particles (circularity ≥0.95) to 10% or less. This parameter control improves fluidity while maintaining manufacturability through controlled hydrolysis and condensation reactions.
Solution Approach 2:
The invention promotes nonspherical particle formation by controlling reaction conditions to limit spherical particle formation. The asymmetric/nonspherical shape (circularity <0.95) provides better fluidity and dispersibility compared to spherical particles, while still allowing controlled production through the sol-gel process.
2Ease of manufacture
If silica particles have a spherical shape, then production is easier, but attachment properties and dispersibility worsen
Solution Approach 1:
The invention changes the particle morphology parameter by controlling the sol-gel reaction to produce particles with circularity predominantly below 0.95. This morphological parameter change improves attachment properties and dispersibility while maintaining production feasibility through controlled reaction conditions.
Solution Approach 2:
The invention promotes asymmetric/nonspherical particle formation to improve attachment and dispersibility. The nonspherical shape creates better interfacial contact and distribution characteristics compared to spherical particles, while the sol-gel process maintains manufacturing efficiency.
3Ease of manufacture
If silica particles have broad particle size distribution, then production is easier, but uniformity and stability worsen
Solution Approach 1:
The invention changes the particle size distribution parameter by controlling the polydispersity index to within 1.05-1.60 and limiting spherical particles to 10% or less. This parameter control ensures uniform composition and stable properties while maintaining ease of production through the sol-gel method.
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
These silica particles exhibit enhanced fluidity, attachment properties, and dispersibility, maintaining shape stability under mechanical load and preventing aggregation, making them suitable for various applications like toners and cosmetics.
Implementation Method 1
a sol-gel method with controlled alkali catalyst and tetraalkoxysilane supply rates
Implementation Method 2
a sol-gel method with controlled alkali catalyst and tetraalkoxysilane supply rates
Implementation Method 3
Hydrophobization treatment of silica particles
Data Source
AI summary
The invention provides silica particles including primary particles, the primary particles having a volume average particle diameter of from about 80 nm to about 300 nm, a particle size distribution index of from about 1.10 to about 1.40, an average circularity of from about 0.70 to about 0.92, and a circularity distribution index of from about 1.05 to about 1.50, the silica particles including primary particles having a circularity of about 0.95 or greater at a proportion of about 10% or less by number of particles.