Hydrolyzed Epoxy-Silane Coating for Ophthalmic Lenses
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Solution Overview
Problem
Existing coatings for ophthalmic lenses face challenges in achieving rapid curing, stability during coating operations, good abrasion resistance, and dye-tintability, particularly when exposed to moisture, which can compromise their performance.
Innovation Solution
A hydrolyzed epoxy-silane composition combined with silica, dialkyl acrylate, tetrahydrofuryl acrylate, cationic and anionic initiators, urethane acrylate, and hindered alkyl-bis-phenol or amine stabilizers, which form a coating that is both abrasion-resistant and dye-tintable without the need for traditional tint-enhancing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a UV-curable coating composition is applied to provide abrasion resistance, then abrasion resistance is improved, but the coating becomes less tintable
Solution Approach 1:
The coating composition is divided into multiple functional components: silane-modify polymer particles provide abrasion resistance, while separate dye particles provide tintability. This segmentation allows each component to perform its specific function without interfering with the other, resolving the contradiction between abrasion resistance and tintability.
Solution Approach 2:
The invention uses a composite coating system combining silane-modify polymer particles with dye particles. The silane-modify polymer forms a crosslinked network providing mechanical strength and abrasion resistance, while the embedded dye particles maintain optical properties and tintability. This composite approach enables simultaneous achievement of both abrasion resistance and tintability.
2Object-affected harmful factors
If a solvent-free coating composition is used to reduce VOC content, then environmental compatibility is improved, but the coating stability during coating operations deteriorates
Solution Approach 1:
Water serves as an intermediary medium in the coating composition, enabling stable storage and application while allowing for rapid curing. The aqueous-based formulation provides stability during coating operations and enables proper viscosity and flow characteristics, while still achieving fast cure rates through the incorporated photoinitiator system.
Solution Approach 2:
The invention changes the physical-chemical parameters of the coating composition by using water-based vehicles with controlled pH and ionic strength. These parameter adjustments enable stable storage and application characteristics while maintaining rapid curing capability through the photoinitiator system, resolving the contradiction between stability and cure rate.
3Speed
If a coating composition is formulated for rapid curing, then curing speed is improved, but the coating becomes more sensitive to moisture
Solution Approach 1:
The invention extracts and removes moisture from the coating composition through the use of hygroscopic silane-modify polymer particles and controlled water content. This extraction prevents moisture-induced defects while maintaining rapid curing capability, as the limited water present is controlled and does not interfere with the photopolymerization process.
Solution Approach 2:
The invention converts the potential harm of moisture sensitivity into a benefit by using controlled water content and hygroscopic particles. The limited moisture present actually enhances the crosslinking density and final coating properties, while the rapid curing prevents moisture ingress. The formulation turns what would be a defect into an advantage for coating performance.
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 solution provides consistently high abrasion resistance and tintability, maintaining performance even when exposed to moisture, with improved stability and reduced impact on light transmission, as evidenced by the data showing superior results in abrasion resistance and adhesion tests.
Implementation Method 1
A coating photoreactive composition comprising a hydrolyzed epoxysilane and other active ingredients is able to provide an organic dye-tintable abrasion resistant coating
Implementation Method 2
a combination of cationic and anionic initiators
Data Source
AI summary
A coating photoreactive composition comprising a hydrolyzed epoxy-silane and other active ingredients is able to provide an organic dye-tintable abrasion resistant coating without the use of traditional dye-tinting enhancing agents such as polymerizable ethers or polymerizable diethers. The compositions exhibit consistently higher abrasion resistance without significant impact on tintability.