Silica Particle Synthesis via Controlled Alkali Catalyst Concentration

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Solution Overview

Problem

Conventional methods for producing silica particles often result in coarse aggregates and spherical particles, which lack shape stability and high purity, especially when using the sol-gel method.

Innovation Solution

A method involving the preparation of an alkali catalyst solution in an alcohol solvent with a specific concentration, followed by the concurrent supply of tetraalkoxysilane and alkali catalyst, allowing for the generation of atypically shaped silica particles with reduced coarse aggregates and enhanced mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional sol-gel method is used to produce silica particles, then production process is simple, but coarse aggregates and spherical particles are formed resulting in poor shape stability and low purity

Engineering Contradiction:
Improveparticle shape uniformityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the chemical parameters of the reaction system by using specific alkali catalysts (ammonium hydroxide, potassium hydroxide, or sodium hydroxide) at controlled concentrations (0.01-10 wt%), and controlling the molar ratio of alkali catalyst to tetraalkoxysilane (0.001-0.5). These parameter changes prevent coarse aggregate formation and achieve uniform atypical particle shapes while maintaining process simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite reaction system combining tetraalkoxysilane (raw material) with specific alkali catalysts and alcohol solvents. This composite approach where multiple components work synergistically prevents spherical particle formation and achieves the desired atypical particle morphology with high shape stability

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conventional methods are used, then production speed is fast, but particle purity is low due to coarse aggregates

Engineering Contradiction:
Improveparticle purityVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By optimizing the alkali catalyst concentration (0.01-10 wt%) and the molar ratio of alkali catalyst to tetraalkoxysilane (0.001-0.5), the invention achieves rapid hydrolysis and condensation reactions that form uniform particles without coarse aggregates, thereby maintaining high production speed while improving particle purity

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If alkali catalyst is used in conventional amounts, then reaction proceeds quickly, but particle shape stability deteriorates

Engineering Contradiction:
Improveshape stabilityVSAvoidparticle uniformity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention establishes specific parameter ranges for alkali catalyst concentration (0.01-10 wt%) and molar ratio to tetraalkoxysilane (0.001-0.5) that simultaneously achieve rapid reaction and uniform atypical particle shapes. The use of specific alkali catalysts (ammonium, potassium, or sodium hydroxide) at these controlled parameters ensures both shape stability and particle uniformity

Inventive Principle:
Principle #35Parameter changes

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 method produces silica particles with high shape stability and reduced non-uniformity, achieving high purity and mechanical strength while minimizing the use of alkali catalyst and eliminating the need for its removal step.

Implementation Method 1

an alcoholic silica sol obtainable by subjecting an alkyl silicate to hydrolysis and a condensation reaction

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

an alcoholic silica sol obtainable by subjecting an alkyl silicate to hydrolysis and a condensation reaction

Methodology Applied
Scientific EffectCondensation reaction: Chemical Bonding

Implementation Method 3

in the presence of an alkali catalyst such as ammonia

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentUS9416015B2Method of producing silica particles
Publication Date: 2016.08.16 FUJIFILM BUSINESS INNOVATION CORP

AI summary

The invention provides a method of producing silica particles, the method including preparing an alkali catalyst solution containing an alkali catalyst in a solvent including an alcohol, at a concentration of from about 0.6 mol/L to about 0.85 mol/L; and supplying tetraalkoxysilane into the alkali catalyst solution, and concurrently supplying an alkali catalyst into the alkali catalyst solution at a rate of from about 0.1 mol to about 0.4 mol per mole of the total amount of supply of the tetraalkoxysilane supplied in one minute.