Zirconium-Tin Oxide Sol Coating for Lens Hardness
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Solution Overview
Problem
Conventional metal oxide sols used in hard coating agents for plastic lenses have unsatisfactory stability, transparency, adhesiveness, weather resistance, and water resistance, particularly when exposed to ultraviolet irradiation.
Innovation Solution
A method for producing a stable zirconium oxide-tin oxide composite colloidal sol with a refractive index of 1.9 or more, involving the formation of zirconium oxide-tin oxide composite colloidal particles coated with amine-containing Sb2O5 and tungsten oxide-silicon dioxide composite colloidal particles, using a carbonate salt of quaternary ammonium and hydrothermal treatment, to enhance compatibility and dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal oxide sol is used as hard coating agent component, then the sol can be applied to plastic lens surface, but the stability, transparency, adhesiveness, weather resistance, and water resistance of the coating film are unsatisfactory
Solution Approach 1:
The invention divides the coating system into distinct functional segments: core particles (zirconium oxide-tin oxide composite) and shell particles (tungsten oxide-tin oxide composite). This segmentation allows each component to be optimized independently for specific functions (refractive index, stability, transparency) while maintaining overall system performance
Solution Approach 2:
The invention employs composite colloidal particles with a core-shell structure, combining zirconium oxide-tin oxide core with tungsten oxide-tin oxide shell. This composite material approach enables the coating film to simultaneously achieve high refractive index, excellent stability, good transparency, and improved weather resistance that cannot be obtained with single-material sols
2Strength
If metal oxide sol is used to improve surface properties of plastic lens, then hardness and wear resistance can be enhanced, but weather resistance particularly under ultraviolet irradiation remains unsatisfactory
Solution Approach 1:
The invention applies local quality by concentrating tungsten oxide in the shell layer specifically for UV resistance and weather stability, while the zirconium oxide-tin oxide core provides hardness and wear resistance. Each region of the composite particle has optimized properties for its specific function, with the shell acting as a protective barrier against environmental degradation
3Illumination intensity
If zirconium oxide-tin oxide composite colloidal particles are formed with specific particle diameter and composition, then refractive index can be increased to 1.9 or more, but the complexity of controlling particle structure and composition increases
Solution Approach 1:
The invention uses preliminary action by pre-forming zirconium oxide-tin oxide core particles with controlled composition and size before coating them with tungsten oxide-tin oxide shell. This stepwise approach allows precise control of the final particle structure and optical properties without requiring complex simultaneous synthesis of all components
Solution Approach 2:
The invention achieves high refractive index (1.9 or more) by optimizing key parameters: the ratio of zirconium oxide to tin oxide in the core, the thickness and composition of the tungsten oxide shell, and the overall particle diameter. By systematically adjusting these parameters, the desired optical performance is achieved while maintaining manufacturability
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 resulting sol exhibits improved refractive index, bonding strength, weather resistance, antistatic properties, and wear resistance, while maintaining stability across a wide pH range, effectively addressing the limitations of conventional sols.
Implementation Method 1
subjecting the obtained aqueous medium to a hydrothermal treatment at 110 to 300°C
Implementation Method 2
coating the particle surface of the sol containing zirconium oxide-tin oxide composite colloidal particles (A) obtained in the step (a) with amine-containing Sb2O5 colloidal particles
Implementation Method 3
preparing a sol containing tungsten oxide-tin oxide-silicon dioxide composite colloidal particles (B2) obtained by preparing an aqueous solution containing tungstates, stannates and silicates and by removing cations contained in the prepared aqueous solution
Implementation Method 4
a stable zirconium oxide-tin oxide composite colloidal sol with a refractive index of 1.9 or more
Data Source
AI summary
It is intended to provide a stable sol containing zirconium oxide-tin oxide composite colloids to be used for improving the performance such as abrasion resistance, transparency, adhesiveness, water resistance or weather resistance of a dried film obtained by applying a hard coating agent containing colloidal particles to the surface of plastic lens. A production method includes the steps of obtaining a sol containing colloidal particles (A1) in which the surface of particles in a sol containing hydrothermally-processed zirconium oxide-tin oxide composite colloids (A) is coated with amine-containing Sb2O5 colloidal particles; obtaining a sol containing colloids (A2) coated with amine-containing Sb2O5 colloidal particles by performing a hydrothermal treatment at a temperature of from 200 to 350°C; and mixing the sol containing the colloidal particles (A2) and a sol containing tungsten oxide-tin oxide-silicon dioxide composite colloidal particles (B2) and aging the resulting aqueous medium at 20 to 100°C.