Polysiloxane Monomer Composition for Contact Lens Shape Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Silicone hydrogel contact lenses face challenges in maintaining shape stability due to inadequate modulus and elongation at break, while achieving satisfactory surface hydrophilicity and oxygen permeability.

Innovation Solution

A monomer composition comprising a phosphorylcholine group-containing polysiloxane monomer, a phosphorylcholine group-containing methacrylic monomer, a trimethylsiloxysilyl group-containing silicone monomer, a monovinyl ether monomer, hydroxy group-containing monomers, and a crosslinker, with specific content ratios to enhance mechanical strength and hydrophilicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polysiloxane monomer is used to achieve high oxygen permeability and surface hydrophilicity, then oxygen permeability and surface hydrophilicity are improved, but modulus and elongation at break deteriorate

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidmodulus

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite monomer system containing multiple components: a polysiloxane monomer (for oxygen permeability), a crosslinking monomer (for mechanical strength), and a hydrophilic monomer (for surface hydrophilicity). This composite approach allows each component to contribute its advantageous properties while compensating for the weaknesses of individual monomers, achieving both high oxygen permeability and adequate mechanical strength through synergistic material composition.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the compositional parameters of the monomer mixture, specifically controlling the ratios of different monomer components to achieve the desired balance between oxygen permeability and mechanical properties. By adjusting the concentration and type of each monomer in the composition, the patent fine-tunes the final lens properties to simultaneously satisfy optical, mechanical, and surface requirements.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a polysiloxane monomer is used to achieve high oxygen permeability and surface hydrophilicity, then oxygen permeability and surface hydrophilicity are improved, but elongation at break deteriorates

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidelongation at break

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs a composite monomer system where a polysiloxane monomer provides oxygen permeability, a crosslinking monomer enhances mechanical integrity and elongation at break, and a hydrophilic monomer improves surface hydrophilicity. This multi-component composite strategy ensures that the lens maintains both high oxygen permeability and adequate elongation at break through complementary material properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent controls the compositional parameters of the monomer mixture, optimizing the ratios of polysiloxane, crosslinking, and hydrophilic monomers to achieve the desired balance between oxygen permeability and elongation at break. By adjusting these compositional parameters, the patent ensures sufficient material flexibility and durability while maintaining high oxygen transmission.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If MPC is used for copolymerization to introduce phosphorylcholine groups, then surface hydrophilicity is improved, but phase separation occurs between hydrophilic MPC and hydrophobic silicone

Engineering Contradiction:

Improvesurface hydrophilicityVSAvoidphase separation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces a crosslinking monomer as an intermediary component that facilitates compatibility between the hydrophilic phosphorylcholine groups and the hydrophobic silicone backbone. This crosslinking agent acts as a bridge, creating a network structure that prevents phase separation while maintaining the surface hydrophilicity provided by the phosphorylcholine groups, thereby ensuring compositional stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a composite monomer system that includes phosphorylcholine-containing monomers for surface hydrophilicity, silicone monomers for oxygen permeability, and crosslinking monomers for structural integrity. This composite approach ensures homogeneous mixing and prevents phase separation by creating a synergistic material system where each component complements the others, maintaining both surface hydrophilicity and compositional stability.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12180321B2Monomer composition for contact lenses, polymer for contact lenses and method for producing same, and contact lens and method for producing the same

Publication Date: 2024.12.31 NOF CORP

AI summary

Provided is a monomer composition for contact lenses, which uses a polysiloxane monomer to produce a polymer that shows satisfactory surface hydrophilicity and oxygen permeability, and that is excellent in modulus and elongation at break. It has been found that a monomer composition containing a phosphorylcholine group-containing polysiloxane monomer, a monovinyl ether monomer, and the like can achieve the above-mentioned object.