Hydrophilic Elastomer Composition for High Water Uptake
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Solution Overview
Problem
Existing hydrophilic silicone rubbers and other polymers do not effectively absorb moisture, limiting their use in skin-contact and mucosa-contact products, and conventional methods struggle to incorporate alpha-olefin sulfonate surfactants into hydrophobic monomers or pre-polymers due to incompatibility issues.
Innovation Solution
Hydrophilic silicone rubbers are produced by incorporating alpha-olefin sulfonate surfactants through peroxide cross-linking, tin catalyzed condensation, or platinum salt catalyzed cross-linking, allowing for high water uptake capacity, and hydrophilic polyurethanes are created by coupling diisocyanate monomers with hydrophilic monomers or pre-polymers to enhance moisture absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alpha-olefin sulfonate surfactants are incorporated into hydrophobic polymers to increase hydrophilicity, then water absorption capacity is improved, but compatibility and ease of manufacture deteriorate due to mixing difficulties
Solution Approach 1:
The patent employs peroxide as an intermediary substance that facilitates the incorporation of hydrophilic surfactants into hydrophobic polymer matrices. The peroxide cross-linking mechanism enables the surfactant molecules to be integrated during the curing process, overcoming the inherent incompatibility between hydrophilic and hydrophobic phases that would otherwise prevent effective mixing and incorporation.
2Reliability
If conventional cross-linking methods are used to produce medical grade silicone rubbers, then biocompatibility is improved, but water absorption capacity remains insufficient
Solution Approach 1:
The patent creates a composite material system by combining hydrophobic silicone rubber base polymers with hydrophilic alpha-olefin sulfonate surfactants. This composite approach allows the material to maintain the biocompatibility and mechanical properties of the silicone rubber while incorporating the water-absorbing capabilities of the sulfonate groups, achieving both medical-grade safety and moisture management functionality.
3Ease of operation
If surface modification is applied to create hydrophilic surfaces, then surface hydrophilicity is improved, but bulk moisture uptake is limited
Solution Approach 1:
The patent merges the surface modification approach with bulk incorporation by integrating hydrophilic surfactant molecules throughout the entire polymer matrix during cross-linking. This combines the benefits of surface hydrophilicity (for initial contact) with bulk moisture uptake capability (for sustained absorption), as the surfactants are distributed throughout the material rather than confined to the surface.
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 materials can absorb up to 500% of their weight in water, making them suitable for moisture control in medical and non-medical devices, with improved biocompatibility and moisture management properties.
Implementation Method 1
the peroxide cross-linking of vinyl containing silicone prepolymers
Implementation Method 2
the tin salt catalyst induced cross-linking of silanol containing silicone prepolymers
Implementation Method 3
the platinum salt induced crosslinking of vinyl and SiH containing silicone prepolymers
Implementation Method 4
hydrophilic silicone-based rubber materials having high water uptake capacity
Data Source
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AI summary
This invention relates to a rubbery or elastomeric polymer material taking up more than 5% by weight of water and at most 500 % by weight of water after immersion in demineralized water at room temperature for a sufficient time to reach saturation, comprising: (a) repeating units from one or more hydrophobic organic monomers, and (b) repeating units from one or more monomers (a) being modified with one or more hydrophilic side groups. The rubbery or elastomeric polymer material may be in the form of a sheet, a foam, a coating adapted for adhesion to a substrate, or a fiber. This invention also relates to processes, polymerizable compositions, and foaming compositions for producing such rubbery or elastomeric polymer materials.