Reactive Monomer-Dispersed Silica Sol Stability
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Solution Overview
Problem
Colloidal silica particles in reactive monomer-dispersed silica sols can cause polymerization or degradation of the reactive monomer due to solid acidity, leading to instability and deterioration of the sol and cured polymer articles.
Innovation Solution
Bonding alkaline earth metal ions, such as calcium or magnesium, to the surface of colloidal silica particles in a ratio of 0.001 to 0.2 pieces per square nanometer to reduce solid acidity, and using a production method that involves dissolving these ions in an organic solvent-dispersed silica sol or aqueous silica sol before exchanging the dispersion medium with a reactive monomer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If colloidal silica particles are dispersed in reactive monomer, then the composite material can improve polymer properties such as elasticity modulus and hardness, but the solid acidity of silica particle surfaces causes polymerization or degradation of the monomer, impairing sol stability
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance that bonds to both the colloidal silica particle surface and the reactive monomer. This coupling agent acts as a mediator that prevents direct contact between the acidic silica surface and the monomer, thereby preventing unwanted polymerization or degradation while maintaining the composite material's enhanced mechanical properties.
Solution Approach 2:
The surface properties of the colloidal silica particles are modified by changing the chemical parameters of the particle surface through silane treatment. This changes the surface from acidic and reactive toward monomer polymerization to a more stable surface that is compatible with the monomer, thereby improving sol stability while preserving the reinforcing effect on polymer properties.
2Illumination intensity
If colloidal silica particles with small particle diameters are used to maintain polymer transparency, then optical loss is minimized, but the solid acidity still causes monomer polymerization and sol instability
Solution Approach 1:
The silane coupling agent serves as a protective intermediary layer on the surface of small-diameter colloidal silica particles. This layer prevents the acidic particle surfaces from contacting and degrading the monomer, allowing the use of small particles for transparency without sacrificing sol stability.
3Ease of manufacture
If reactive monomer is mixed with organic solvent-dispersed silica sol and solvent is removed, then reactive monomer-dispersed silica sol is obtained, but the solid acidity causes monomer polymerization during production
Solution Approach 1:
The silane coupling agent is applied to the colloidal silica particle surfaces in advance, before the monomer is introduced and before solvent removal. This preliminary surface treatment ensures that the particles are protected against causing monomer polymerization throughout the subsequent production steps, enabling stable manufacturing of the reactive monomer-dispersed silica sol.
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 approach results in a reactive monomer-dispersed silica sol with enhanced stability and reduced likelihood of polymer degradation, producing cured articles with improved durability and transparency.
Implementation Method 1
containing a colloidal silica particle in which an alkaline earth metal ion is bonded to a surface of the colloidal silica particle
Implementation Method 2
cured by the irradiation of activating energy rays such as ultraviolet (UV) rays, electron beams, γ-rays and X rays
Data Source
AI summary
Colloidal silica particles dispersed in a reactive monomer may cause the polymerization, degradation, or the like of the reactive monomer by an action of the solid acidity of the surfaces of the particles and a monomer may be polymerized during a process for producing a monomer-dispersed silica sol, or a stable silica sol may not be obtained. In addition, a polymer of a resin formed article etc. obtained by curing a monomer-dispersed silica sol may be deteriorated, degraded, or the like with time. Therefore, there are provided a reactive monomer-dispersed silica sol having high stability by reducing the solid acidity of the surfaces of the colloidal silica particles contained in the reactive monomer-dispersed silica sol, and a production method thereof, and a curable composition using the reactive monomer-dispersed silica sol, and a cured article in which the deterioration, the degradation, or the like of the polymer is suppressed. The present invention provides a reactive monomer-dispersed silica sol containing a colloidal silica particle in which an alkaline earth metal ion is bonded to a surface of the colloidal silica particle.