Polysiloxane with Hydroxyl Side Chains for Ophthalmic Devices

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Solution Overview

Problem

Polysiloxanes with hydrophilic side chains, such as those described in existing patents, suffer from insufficient hydrophilicity and poor mechanical durability due to ether bond degradation, leading to compatibility issues with other hydrophilic monomers and reduced strength in ophthalmic devices.

Innovation Solution

A polysiloxane with terminal (meth)acryl groups and a hydrophilic side chain featuring an alkyl group with three hydroxyl groups, which is highly compatible with other hydrophilic monomers and resistant to oxidation and hydrolysis, ensuring improved mechanical strength and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polysiloxane with ether bond-containing hydrophilic side chains (such as polyoxyethylene groups) is used, then hydrophilicity and oxygen permeability are improved, but mechanical durability deteriorates due to oxidation and hydrolysis degradation

Engineering Contradiction:

Improvehydrophilicity and oxygen permeabilityVSAvoidmechanical strength durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention changes the chemical structure parameter of the hydrophilic side chain from ether bonds to hydroxyl groups. Specifically, it uses alkyl groups with three hydroxyl groups (formula (3)) instead of polyoxyethylene groups, fundamentally altering the chemical composition to eliminate the degradation-prone ether bonds while maintaining hydrophilicity through the hydroxyl groups.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the unstable ether bond-containing side chains with stable hydroxyl group-containing side chains. The hydroxyl groups provide the necessary hydrophilicity without the degradation issues of ether bonds, effectively creating a more durable material that doesn't require frequent replacement due to mechanical degradation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If a polysiloxane with alkyl group side chains having ether bonds and hydroxyl groups is used, then some hydrophilicity is achieved, but compatibility with other hydrophilic monomers remains insufficient

Engineering Contradiction:

ImprovehydrophilicityVSAvoidcompatibility with hydrophilic monomers

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention optimizes the hydrophilic side chain structure by using alkyl groups with three hydroxyl groups (formula (3)) where the alkyl chain length is controlled (m=2-10, p=1-6). This specific structural parameter configuration enhances compatibility with hydrophilic monomers like (meth)acrylic acid and N-vinyl-2-pyrrolidone while maintaining adequate hydrophilicity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If polysiloxane with ether bond-containing side chains is used to achieve hydrophilicity, then oxygen permeability is improved, but the polymer shows poor mechanical strength durability in phosphate buffer solution

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidmechanical strength durability in phosphate buffer solution

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention extracts and removes the ether bond component from the hydrophilic side chain structure. By eliminating the ether bonds that are susceptible to hydrolysis and oxidation in phosphate buffer solutions, the patent retains the oxygen permeability benefits of polysiloxane while removing the source of mechanical degradation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention creates a composite structure combining the polysiloxane main chain with hydroxyl group-containing alkyl side chains. This composite approach maintains the oxygen permeability of the polysiloxane backbone while the hydroxyl-containing side chains provide hydrophilicity and resistance to hydrolysis, achieving both requirements simultaneously.

Inventive Principle:

Principle #40Composite materials

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 polysiloxane provides a polymer with enhanced compatibility, hydrophilicity, and mechanical durability, suitable for ophthalmic devices like contact lenses and intraocular lenses, maintaining strength even in phosphate buffer solutions.

Implementation Method 1

a polysiloxane having polymerizable groups at both terminals... is copolymerizable with other polymerizable monomer for preparing ophthalmic devices to form a crosslinking structure

Methodology Applied

Scientific EffectCopolymerization: Chemical Bonding

Implementation Method 2

the hydrophilic side chain has an alkyl group having three hydroxyl groups... is very compatible with other hydrophilic monomers

Methodology Applied

Scientific EffectHydrogen bonding: Chemical Bonding

Implementation Method 3

provides a (co)polymer having high oxygen permeability

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3085727B1Silicone and use thereof

Publication Date: 2017.06.21 SHIN ETSU CHEMICAL CO LTD

AI summary

One of the purposes of the present invention is to provide a polysiloxane which has polymerizable groups at both terminals, is very compatible with another hydrophilic monomer, and provides a (co)polymer having improved durability of mechanical strengths. The present invention provides a compound represented by the formula (1) having a group represented by the formula (3) as a hydrophilic side chain, which is characterized in that the hydrophilic side chain has an alkyl group having three hydroxyl groups and no ether bond. Further, the present invention provides a method for preparing the silicone of formula (1).