High-Refractive-Index Optical Coatings for Crack and Water Resistance
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Solution Overview
Problem
Existing abrasion- and scratch-resistant coatings for optical articles, particularly organic glass lenses, are prone to cracking, peeling, and water sensitivity, while lacking protection from UV light and maintaining transparency.
Innovation Solution
A curable composition comprising epoxy compounds, silane compounds, and a combination of titanium and tin oxide colloids, with specific weight ratios, to enhance durability, adhesion, and UV protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If titanium oxide is used as a metal oxide for a hard coat layer, then UV protection is provided, but photoactivation effect causes decomposition of organic substances and crack formation
Solution Approach 1:
The patent combines titanium oxide (providing UV protection) with zirconium oxide (providing high refractive index and low photocatalytic activity) in a composite coating layer. This merging allows the coating to simultaneously achieve UV protection, high refractive index, and reduced crack formation by distributing the functional properties across multiple materials.
Solution Approach 2:
The invention uses a composite material system consisting of titanium oxide, zirconium oxide, and silane-based organic substances. This composite approach allows the coating to integrate multiple functions: UV absorption (TiO2), high refractive index (ZrO2), and structural flexibility/crack resistance (silane matrix), resolving the contradiction between UV protection and crack formation.
2Object-affected harmful factors
If titanium oxide is used in the hard coat, then UV protection is achieved, but water penetration through cracks causes delamination and reduced durability
Solution Approach 1:
The patent merges titanium oxide with zirconium oxide and silane compounds to create a composite coating that simultaneously provides UV protection and enhanced durability. The silane-based matrix fills and seals potential cracks, preventing water penetration, while the TiO2-ZrO2 composite maintains UV protection and high refractive index properties.
Solution Approach 2:
The invention changes the chemical composition parameters of the coating by introducing zirconium oxide and silane compounds in specific ratios. This parameter modification transforms the coating from a crack-prone TiO2-based system to a more durable composite system with improved water resistance and long-term stability while maintaining UV protection.
3Illumination intensity
If high refractive index materials are used to improve optical performance, then transparency is enhanced, but the coating becomes more sensitive to environmental conditions
Solution Approach 1:
The patent employs a composite material system where zirconium oxide provides high refractive index for optical performance, while titanium oxide and silane compounds provide environmental stability. The silane-based organic matrix binds the inorganic particles, creating a cohesive structure that resists environmental degradation while maintaining the high refractive index needed for transparency.
Solution Approach 2:
The invention applies different materials with specific local functions: zirconium oxide particles provide high refractive index in specific regions, titanium oxide provides UV protection, and the silane matrix provides environmental resistance. This local quality distribution allows the coating to achieve high transparency while maintaining reliability under environmental conditions.
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 composition provides high refractive index coatings with reduced cracking, peeling, and water sensitivity, maintaining transparency and scratch resistance, while protecting against UV degradation.
Implementation Method 1
comprising a cross-linked network structure formed from a curable composition
Implementation Method 2
bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom
Data Source
AI summary
The invention relates to a curable composition for an abrasion-and/or scratch-resistant coating, comprising at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom and at least one group comprising an epoxy function linked to the silicon atom through a carbon atom, and/or a hydrolyzate thereof, at least one silane compound of formula Z1Z2SiR1R2, and/or a hydrolyzate thereof, in an amount of 1 to 10 %, relative to the dry extract weight of the composition, in which Z1 and Z2 independently represent a hydrolyzable group or a hydrogen atom, R1 and R2 independently represent a monovalent organic group devoid of epoxy group and linked to the silicon atom through a carbon atom, colloidal particles of metal oxide or metalloid oxide, comprising (c1) colloidal particles of titanium oxide, and (c2) colloidal particles of tin oxide, at least one curing catalyst, wherein tin oxide expressed as SnOz and titanium oxide expressed as TiO2 are present in the composition in a weight ratio of TiO2/(TiO2+SnO2) ranging from 35 % to 75 %. The resulting coating can be formed on an optical article.