Epoxy-Silane Coating for Ophthalmic Lenses
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Solution Overview
Problem
Current coatings for polymeric substrates, such as ophthalmic lenses, face challenges in achieving rapid curing, excellent adhesion, superior mar resistance, and quick tintability while maintaining solution stability and serving as a suitable base for antireflective coatings, with existing solutions either lacking in mar resistance or requiring long cure times and primers.
Innovation Solution
A coating composition comprising epoxy-silane or acryloyl-silane polymers combined with dye-absorbing oligomers and organofunctional trialkoxysilane monomers, which are hydrolyzed with deionized water and optionally catalyzed, along with photoinitiators and additives, to create a rapidly cured, highly tintable, and stable film that enhances adhesion and mar resistance without the need for primers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If radiation cured coatings are used, then rapid curing is achieved, but mar resistance deteriorates
Solution Approach 1:
The patent combines radiation-curable monomers with thermally-curable monomers in a single coating formulation. The radiation-curable component provides rapid curing (within 1 minute), while the thermally-curable component builds mar resistance and mechanical strength. This merging of two different curing mechanisms allows the coating to achieve both fast processing and durable performance that neither component could achieve alone.
Solution Approach 2:
The coating uses a composite system containing both radiation-curable monomers (acrylates, oxiranes) and thermally-curable monomers (siloxanes, organometallics) along with polymerization initiators and catalysts. This composite material approach allows the coating to exhibit dual curing behavior: rapid initial cure from radiation exposure followed by continued curing and strength development from thermal activation, resolving the contradiction between speed and strength.
2Speed
If radiation cured coatings are used, then rapid curing is achieved, but adhesion of subsequently applied antireflective coatings deteriorates
Solution Approach 1:
The patent merges radiation-curable and thermally-curable monomers to create a coating that provides both rapid initial curing and enhanced adhesion. The thermally-curable component (siloxanes, organometallics) forms strong adhesive bonds with the polymeric substrate and creates a stable base layer that promotes adhesion of subsequently applied antireflective coatings, while the radiation-curable component ensures rapid processing.
3Strength
If thermally cured coatings are used, then mar resistance is improved, but cure time deteriorates
Solution Approach 1:
The coating formulation includes both radiation-curable monomers and thermally-curable monomers with their respective initiators and catalysts pre-mixed. Upon application, radiation exposure immediately triggers the radiation-curable component to cure within 1 minute, providing rapid initial protection. The thermally-curable component then continues the curing process over several hours at elevated temperatures to develop full mar resistance and mechanical properties. This preliminary rapid cure followed by continued thermal curing resolves the contradiction between time and strength.
4Strength
If thermally cured coatings are used, then mar resistance is improved, but dye absorption deteriorates
Solution Approach 1:
The patent combines radiation-curable monomers known for excellent dye absorption properties with thermally-curable monomers providing mar resistance. The radiation-curable component (acrylates, oxiranes) provides rapid dye uptake and tintability, while the thermally-curable component (siloxanes, organometallics) provides the durable mar-resistant base. This merging allows the coating to achieve both quick tinting and long-term durability.
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 results in coatings that are rapidly cured, highly stable, exhibit excellent adhesion, superior mar resistance, and provide a suitable base for antireflective coatings, with improved clarity, transparency, and light transmission, addressing the limitations of previous technologies.
Implementation Method 1
The coating composition comprises from 20 to 80 weight percent one or more organofunctional trialkoxysilane monomers... deionized water to effect hydrolysis with or without the aid of an acid or base catalyst
Implementation Method 2
Coatings of the former type usually contain acrylate or acrylate and oxirane functional compounds that are polymerized on exposure to radiation of a particular wavelength that is capable of acting upon a polymerization initiator to commence polymerization
Data Source
AI summary
A coating composition and coating for ophthalmic lenses and other polymeric substrates having a unique combination of excellent solution stability, rapid cure rate, improved mar resistance, rapid dye absorption, and improved receptivity towards antireflective coatings. The coating comprises an abrasion resistant polymer and a dye-absorption-enhancing oligomer. The coating is tinted after curing with a dye to provide light absorbency in the coating.