UV-blocking Silicone Hydrogel Contact Lens Composition

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Solution Overview

Problem

Manufacturing silicone hydrogel contact lenses with both high UV-blocking efficiency and hydrophilicity is challenging due to the difficulty in combining hydrophobic silicon-based materials with hydrophilic surfaces and UV-blocking monomers.

Innovation Solution

A UV-blocking silicone hydrogel composition is developed, comprising a hydrophilic silicone macromer, UV-blocking monomer, first hydrophilic monomer, crosslinker, and polymerization initiator, which includes specific chemical structures and weight percentages to achieve both high moisture retention and UV-blocking efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a hydrophobic silicon-based material is used to manufacture contact lens, then oxygen permeability is improved, but surface hydrophilicity deteriorates

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidsurface hydrophilicity

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs composite materials by combining hydrophobic silicon-based polymers with hydrophilic monomers (NVP, HEMA) and UV-blocking monomers in a copolymerization system. This creates a multi-phase hydrogel structure where hydrophobic domains provide oxygen permeability while hydrophilic domains provide surface wettability and UV protection, resolving the contradiction between oxygen transmission and surface hydrophilicity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention applies local quality by creating distinct phases within the contact lens material: hydrophobic silicon-based polymer regions maintain high oxygen permeability, while hydrophilic monomer-rich regions provide surface wettability and UV-blocking functionality. The differential composition at different locations (bulk vs. surface) allows simultaneous optimization of oxygen transport and surface properties

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If UV-blocking monomer is incorporated into silicone hydrogel composition, then UV-blocking efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:

ImproveUV-blocking efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges multiple functions into a single copolymerization process: UV protection, hydrophilicity enhancement, and lens formation all occur simultaneously in one manufacturing step. By incorporating UV-blocking monomers (benzotriazole or benzophenone derivatives) into the base silicone hydrogel formulation, the invention eliminates the need for separate UV coating or post-processing steps, thereby reducing manufacturing complexity despite adding UV functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The UV-blocking monomers used in the invention serve multiple functions: they provide UV absorption, contribute to the hydrogel network structure, and enhance surface wettability when combined with hydrophilic monomers. This multi-functionality reduces the need for additional separate components or processing steps, simplifying the overall manufacturing process while achieving UV protection

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If hydrophilic monomer is added to increase surface wettability, then surface hydrophilicity is improved, but oxygen permeability may deteriorate

Engineering Contradiction:

Improvesurface wettabilityVSAvoidoxygen permeability

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the concentration parameters of hydrophilic monomers (NVP and HEMA) within specific ranges (5-20 wt% and 5-15 wt% respectively) to achieve the desired balance. By carefully controlling the amount of hydrophilic monomer content, the invention maintains sufficient surface wettability for comfort while preserving adequate oxygen permeability through the lens material, preventing the deterioration of oxygen transport

Inventive Principle:

Principle #35Parameter changes

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 results in a silicone hydrogel contact lens with excellent UV-blocking capabilities (UVA < 10% and UVB < 1%) and superior hydrophilicity, reducing lipid and protein deposits and enhancing wear comfort.

Implementation Method 1

a polymerization initiator... to form a three-dimensional network structure

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

an UV-blocking monomer... UV-blocking efficiency (UVA < 10% and UVB < 1%)

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9482788B2UV-blocking silicone hydrogel composition and silicone hydrogel contact lens containing thereof

Publication Date: 2016.11.01 PEGAVISION CORP

AI summary

The present disclosure provides a UV-blocking silicone hydrogel composition including a hydrophilic silicone macromer, a UV-blocking monomer, a first hydrophilic monomer, a crosslinker and a polymerization initiator. The hydrophilic silicone macromer has a general formula: V-L-S-(L′-V′)x, wherein V and V′ are independently ethylenically-based polymerizable groups, L and L′ are independently a covalent bond or a linkage group, S is a siloxane group having a chemical structure such asand x is 0 or 1. A silicone contact lens containing the UV-blocking silicone hydrogel composition is also provided herein.