Curable Coating Composition for Ophthalmic Lens Scratch Resistance
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Solution Overview
Problem
Existing ophthalmic lens coatings lack sufficient scratch resistance, particularly on solar lenses with reflective fronts, which are prone to damage from environmental factors and reduce vision quality and aesthetic appeal.
Innovation Solution
A radiation-curable coating composition comprising highly functional poly(meth)acrylate compounds and unsaturated silanes, representing at least 95% of the polymerizable compounds, which provides enhanced scratch resistance without compromising optical or mechanical properties and is robust against heat and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hard coat is applied to improve abrasion resistance, then scratch resistance improves, but the coating becomes brittle and prone to cracking
Solution Approach 1:
The patent uses a composite coating system consisting of a primer layer, a hard coat layer with specific composition (epoxy alkoxysilane, polyfunctional acrylate monomer, UV absorber), and an anti-reflection coating. This multi-layer composite structure allows each layer to perform its specific function while working together to provide overall protection without brittleness.
Solution Approach 2:
The patent specifies precise compositional parameters for the hard coat, including the use of at least one epoxy alkoxysilane, at least one polyfunctional acrylate monomer, and at least one UV absorber. By controlling these chemical parameters and their ratios, the coating achieves optimal balance between scratch resistance and flexibility.
2Strength
If the total thickness of anti-reflection coating is increased to improve protection, then abrasion resistance improves, but the optical performance deteriorates due to increased light scattering
Solution Approach 1:
The patent applies different properties to different layers: the primer layer provides adhesion, the hard coat layer provides scratch resistance with controlled thickness, and the anti-reflection layers provide optical performance. Each layer is optimized locally for its specific function, allowing the hard coat to be sufficiently thick for protection without compromising overall optical performance.
Solution Approach 2:
The patent uses a composite multi-layer structure where the hard coat is integrated with primer and anti-reflection layers. This composite approach allows the hard coat to provide protection while the anti-reflection layers maintain optical performance through their specific material composition and thickness control.
3Manufacturing precision
If conventional coating materials are used to maintain optical clarity, then transparency is maintained, but scratch resistance is insufficient
Solution Approach 1:
The patent employs a composite hard coat formulation combining epoxy alkoxysilane, polyfunctional acrylate monomer, and UV absorber. This composite material system achieves both high scratch resistance and optical clarity, overcoming the limitation of conventional single-material coatings.
Solution Approach 2:
The patent modifies the chemical composition parameters of the coating by introducing specific functional compounds (epoxy alkoxysilane for crosslinking and strength, polyfunctional acrylate for polymerization and clarity, UV absorber for stability). These parameter changes enable simultaneous achievement of scratch resistance and optical transparency.
4Manufacturing precision
If mirror coating is applied to solar lenses to improve aesthetics and light reflection, then reflective performance improves, but abrasion resistance deteriorates making the coating easily damaged
Solution Approach 1:
The patent segments the coating system into distinct functional layers: primer layer for adhesion, hard coat layer for mechanical protection, and anti-reflection/mirror layers for optical performance. This segmentation allows the hard coat to protect the underlying reflective coating without compromising its reflective properties.
Solution Approach 2:
The patent uses a composite multi-layer coating system where the hard coat material (epoxy alkoxysilane-based) provides abrasion resistance to protect the underlying mirror or anti-reflection coating. This composite structure allows the reflective layers to maintain their optical performance while being protected by the durable hard coat.
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 coating achieves superior scratch resistance and adhesion to lens substrates, maintaining optical performance and resisting abrasion and heat, while avoiding brittleness and the need for heating in the manufacturing process.
Implementation Method 1
a radiation-curable coating composition comprising at least one poly(meth)acrylate compound comprising at least 6 (meth)acrylate groups, at least one unsaturated silane compound, and at least one initiator, preferably a photoinitiator
Implementation Method 2
at least one unsaturated silane compound
Implementation Method 3
unsaturated silane compound... representing at least 95% of the weight of polymerizable compounds
Data Source
AI summary
The present invention relates to a curable coating composition, especially a radiation curable coating composition comprising at least one poly(meth)acrylate compound comprising at least 6 (meth)acrylate groups, at least one unsaturated silane compound, and at least one photoinitiator. Said at least one poly(meth)acrylate compound comprising at least 6 (meth)acrylate groups and said at least one unsaturated silane compound represent at least 95% of the weight of polymerizable compounds present in the composition. Upon radiation-curing, the composition provides an abrasion- and/or scratch-resistant coating.