Acryloyl-Functionalized Polydimethylsiloxane Synthesis

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Solution Overview

Problem

Acryloyl-functionalized polydimethylsiloxanes face challenges in achieving a balance between oxygen permeability and hydrophilicity, often resulting in hydrophobicity and corneal staining, while copolymerization with hydrophilic monomers can lead to phase separation and poor optical quality, and may contain undesirable impurities like epoxides that are irritating.

Innovation Solution

The method involves hydrosilylating a composition with acryloyl compounds and a siloxanyl group-containing compound to produce a balanced acryloyl-functionalized polydimethylsiloxane with improved transparency, hydrophilicity, mechanical properties, and oxygen permeability, while minimizing impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acryloyl-functionalized polydimethylsiloxane is used to increase oxygen permeability, then oxygen permeability is improved, but hydrophobicity increases causing corneal staining

Engineering Contradiction:
Improveoxygen permeabilityVSAvoidhydrophobicity causing corneal staining
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters by incorporating hydrophilic monomers (2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate) at specific concentrations (5-50 wt%) into the polydimethylsiloxane matrix. This parameter change transforms the surface properties from hydrophobic to hydrophilic, reducing corneal staining while preserving oxygen permeability through the siloxane backbone structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system combining polydimethylsiloxane (for oxygen permeability) with hydrophilic monomers (for wetting properties). This composite approach allows simultaneous achievement of high oxygen permeability (Dk > 100) and improved hydrophilicity, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If copolymerization with hydrophilic monomer is performed to increase hydrophilicity, then hydrophilicity is improved, but phase separation occurs due to static repulsion between polar hydroxyl group and nonpolar siloxanyl group

Engineering Contradiction:
ImprovehydrophilicityVSAvoidphase separation
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent optimizes the concentration parameters of hydrophilic monomers within specific ranges (2-hydroxyethyl methacrylate: 5-50 wt%, 2-hydroxyethyl acrylate: 5-30 wt%) to achieve sufficient hydrophilicity while maintaining compositional stability. This controlled parameter adjustment prevents excessive phase separation by balancing hydrophilic-hydrophobic interactions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces hydrophilic groups at specific local positions within the polymer matrix, creating micro-environments with appropriate polarity. This localized modification allows hydrophilic monomers to be distributed in a manner that promotes uniform mixing rather than macro-phase separation, maintaining optical quality while achieving desired wetting properties.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If acryloyl-functionalized polydimethylsiloxane is synthesized by addition reaction between epoxy compound and (meth)acrylic acid, then acryloyl functionality is introduced, but undesirable impurities like epoxide or diol moieties remain at high concentrations

Engineering Contradiction:
Improveacryloyl functionality introductionVSAvoidimpurity concentration
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent removes the problematic epoxy compound and (meth)acrylic acid reaction pathway from the synthesis process. Instead, it uses alternatively prepared acryloyl-functionalized polydimethylsiloxane starting materials, thereby extracting and eliminating the source of epoxide and diol impurities from the manufacturing process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs pre-synthesized acryloyl-functionalized polydimethylsiloxane as a starting material rather than performing the problematic in-situ reaction. This approach uses a disposable, pre-prepared reagent that has already been optimized to minimize impurity formation, simplifying the manufacturing process while ensuring low impurity levels in the final product.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 resulting compositions exhibit excellent optical quality, hydrophilicity, and mechanical properties, making them suitable for ophthalmic lenses with low modulus of elasticity and reduced impurity concentrations, thus addressing the issues of hydrophobicity and impurities in existing formulations.

Implementation Method 1

Acryloyl-functionalized linear polydimethylsiloxanes can have a satisfactory oxygen permeability

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

phase separation can occur due to the static repulsion between the polar hydroxyl group and the nonpolar siloxanyl group

Methodology Applied
Scientific EffectPhase separation:

Data Source

PatentEP2049922B1Acryloyl materials for molded plastics
Publication Date: 2016.07.13 JOHNSON & JOHNSON VISION CARE INC
  • EP2049922B1 patent drawingFigure 1~2
  • EP2049922B1 patent drawingFigure 3~4
  • EP2049922B1 patent drawingFigure 5

AI summary

In one aspect, the invention relates to methods of synthesizing acryloyl compounds, comprising the step of hydrosilylating a compound having the structure: (a) or (b), with a compound having the structure A-H, wherein A comprises a siloxanyl group, to yield a compound having the structure: (c) or (d). Compounds and compositions produced thereby can effectively attain a satisfactory balance between high oxygen permeability and hydrophilicity while achieving an acceptably low concentration of undesirable impurities. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.