Irregular Silica Particles for Toner Fluidity and Adherence

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Solution Overview

Problem

Existing silica particles used in toners, cosmetics, and abrasives often lack optimal shape and size distribution, leading to poor fluidity and adherence issues, making them difficult to disperse and maintain shape under mechanical loads.

Innovation Solution

Silica particles with an average diameter of 100-500 nm, a particle size distribution index of 1.40-1.80, and an average roundness of 0.5-0.85, treated with an organosilicon compound to achieve hydrophobization, are produced using a method involving an alkali catalyst solution and controlled supply rates of tetraalkoxysilane, ensuring 95% or more particles satisfy a specific roundness and diameter formula, resulting in irregular shapes that maintain fluidity and adherence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If silica particles are made spherical with uniform size distribution, then manufacturing precision is improved, but fluidity and adherence properties deteriorate

Engineering Contradiction:
Improveparticle size uniformityVSAvoidfluidity and adherence
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent deliberately creates asymmetric particle shapes (irregular, non-spherical geometries) to improve fluidity and adherence properties. The silica particles are designed with varying shapes and size distributions rather than uniform spherical forms, allowing better interaction with surrounding materials while maintaining manufacturability through controlled synthesis processes.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If silica particles are made with irregular shapes to improve fluidity, then ease of operation is improved, but manufacturing precision deteriorates

Engineering Contradiction:
ImprovefluidityVSAvoidshape uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs parameter changes in the synthesis process, specifically controlling pH levels, temperature, and reagent addition rates to produce silica particles with desired irregular shapes and size distributions. By adjusting these parameters, the process achieves both fluidity improvement and acceptable manufacturing precision through statistical control of particle formation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If silica particles are produced with narrow size distribution, then manufacturing precision is improved, but particle functionality deteriorates

Engineering Contradiction:
Improvesize distribution uniformityVSAvoidparticle performance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent segments the silica particle population into different size classes and shape categories, with each segment optimized for specific functions. This segmentation allows simultaneous achievement of manufacturing precision within each segment while maintaining overall particle functionality through the diverse size and shape distribution that enhances performance in applications like toners and cosmetics.

Inventive Principle:
Principle #1Segmentation

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 silica particles exhibit excellent fluidity, dispersibility, and mechanical stability, preventing embedment in objects and maintaining shape integrity under load, enhancing their performance in applications like toners and cosmetics.

Implementation Method 1

treated with an organosilicon compound to achieve hydrophobization

Methodology Applied
Scientific EffectHydrophobization: Hydrophobe

Implementation Method 2

a method involving an alkali catalyst solution and controlled supply rates of tetraalkoxysilane

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

a method involving an alkali catalyst solution and controlled supply rates of tetraalkoxysilane

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentUS9187502B2Silica particles and method for producing the same
Publication Date: 2015.11.17 FUJIFILM BUSINESS INNOVATION CORP

AI summary

The present invention provides silica particles including primary particles, the primary particles having an average particle diameter in a range of from about 100 nm to about 500 nm, a particle size distribution index in a range of from about 1.40 to about 1.80, and an average roundness in a range of from about 0.5 to about 0.85, and about 95% or more, by number of particles, of the primary particles satisfying following Formula (1) with respect to a roundness (R) and a particle diameter (D) (nm):R=α×D/1000+β  Formula (1)(−2.5≦α≦−0.9, 0.8≦β≦1.2).