Polymerizable Composition for Colored Contact Lens Adhesion
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Solution Overview
Problem
Conventional methods for manufacturing colored contact lenses result in discoloration or fading due to poor adhesion of the colored layer, and are either complex or costly.
Innovation Solution
A novel polymerizable composition comprising a composite colorant produced by reacting a colorant precursor with a (methyl)methacryloxy group-containing silane coupling agent, combined with hydrophilic monomers, thickener, crosslinking agent, and initiators, which provides strong adhesion to contact lenses and prevents discoloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a colored layer is formed by printing or transferring a mixture of colorant and hydrophilic monomers on the contact lens surface, then the contact lens can be colored, but the colored layer lacks interaction force with the contact lens causing peeling and discoloration
Solution Approach 1:
The patent uses a composite colorant system consisting of inorganic colorant particles dispersed in a polymerizable composition containing hydrophilic monomers and silane coupling agents. This composite structure provides both coloring function and strong adhesion to the contact lens surface through chemical bonding, eliminating the peeling problem of conventional printed colored layers.
Solution Approach 2:
The silane coupling agent acts as an intermediary between the inorganic colorant particles and the contact lens surface. It forms chemical bonds with both the inorganic colorant and the contact lens material, creating a strong interaction force that prevents peeling and discoloration of the colored layer.
2Reliability
If a transparent protective layer is covered on the colored layer to protect it from damage and discoloration, then the colored layer is protected, but the manufacturing process becomes complicated and costly
Solution Approach 1:
The patent merges the coloring function and protective function into a single integrated layer. The polymerizable composition containing inorganic colorants, hydrophilic monomers, and silane coupling agents forms both the colored layer and the protective layer simultaneously, eliminating the need for a separate transparent protective layer and simplifying the manufacturing process.
Solution Approach 2:
The polymerizable composition serves multiple functions: it provides coloration through inorganic colorants, ensures strong adhesion through silane coupling agents, and forms a protective matrix through polymerization of hydrophilic monomers. This multi-functional composition replaces the need for separate colored and protective layers.
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 ensures long-lasting color retention on contact lenses without fading, with improved adhesion and a simpler manufacturing process compared to conventional methods.
Implementation Method 1
The composite colorant is produced by a reaction of a colorant precursor and a (methyl)methacryloxy group-containing silane coupling agent
Implementation Method 2
a polymerizable composition for coloring contact lenses, comprising a composite colorant and at least one hydrophilic monomer
Data Source
AI summary
The disclosure is related to a polymerizable composition for coloring contact lens, comprising a composite colorant and at least one hydrophilic monomer. The composite colorant is produced by a reaction of a colorant precursor and a (methyl)methacryloxy group-containing silane coupling agent. The colorant precursor is produced by a reaction of a metal oxide and a siloxane compound under alkaline solution.