Siloxane Contact Lens Composition for Oxygen Permeability and Elongation

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Solution Overview

Problem

Conventional soft contact lenses face challenges in balancing oxygen permeability and elongation, where increasing oxygen permeability can lead to breakage, and increasing elongation can reduce oxygen permeability, affecting durability and comfort.

Innovation Solution

A composition for contact lenses comprising a siloxane mixture, tris(trimethylsiloxy)silypropyl methacrylate, and a hydrophilic monomer, with specific weight ratios and monomer formulations to achieve high oxygen permeability and elongation, including a first siloxane monomer with an acryloyl group and a second siloxane monomer with two acryloyl groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxygen permeability is increased, then oxygen transmission improves, but elongation decreases making the lens prone to breakage

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidelongation

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite material system consisting of multiple siloxane monomers with different functional groups (acryloyl, glycidyl, vinyl). This composite approach allows the lens to simultaneously achieve high oxygen permeability through siloxane content while maintaining elongation through the synergistic interaction of different monomer types, resolving the contradiction between oxygen transmission and mechanical strength

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent systematically varies the compositional parameters of the siloxane monomers, including their molecular weights, functional group types, and relative proportions. By optimizing these parameters within specific ranges, the invention achieves the breakthrough of obtaining both high oxygen permeability (Dk>80) and high elongation (>270%), which were previously mutually exclusive

Inventive Principle:

Principle #35Parameter changes

2Strength

If elongation is increased to improve durability, then mechanical strength improves, but oxygen permeability decreases affecting comfort

Engineering Contradiction:

ImproveelongationVSAvoidoxygen permeability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The use of composite siloxane monomer systems with varying functional groups enables the material to achieve both high elongation and high oxygen permeability simultaneously, eliminating the need to sacrifice oxygen transmission for mechanical strength

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different siloxane monomers with specific functional groups are strategically selected to provide localized functional properties: some monomers contribute more to oxygen permeability while others contribute more to mechanical strength, and their combined effect achieves both goals throughout the lens material

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240241292A1Composition for contact lens and contact lens

Publication Date: 2024.07.18 VISCO VISION

AI summary

A composition for a contact lens and a contact lens are provided. The composition for a contact lens includes a siloxane mixture, a tris(trimethylsiloxy)silypropyl methacrylate, and a hydrophilic monomer. The siloxane mixture includes a first siloxane monomer and a second siloxane monomer. The first siloxane monomer has an acryloyl group. The second siloxane monomer has two acryloyl groups. A weight ratio of the siloxane mixture to the tris(trimethylsiloxy)silypropyl methacrylate is between about 27.5:1 and about 0.29:1.