Patterned Silicone Adhesive Coating for Breathable Wound Dressings
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Solution Overview
Problem
Silicone pressure-sensitive adhesives used in medical products, such as wound dressings, have limited oxygen and moisture permeability due to their continuous coating, which reduces breathability, and are incompatible with common hydrophilic wound dressing materials, making conventional pattern coating methods difficult.
Innovation Solution
A method for applying a patterned silicone adhesive coating to a substrate by coating a silicone precursor onto an apertured support layer or a mold with recesses, followed by thermal curing, allowing for direct bonding to hydrophilic surfaces without a primer, and using a mold with larger apertures to accommodate the viscous precursor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a continuous coating of silicone adhesive is applied to the substrate, then adhesion strength is improved, but breathability (oxygen and moisture permeability) deteriorates
Solution Approach 1:
The continuous silicone adhesive coating is segmented into a discontinuous patterned coating, creating separate adhesive regions separated by non-adhesive regions. This segmentation allows the coating to maintain adhesion strength in the adhesive regions while permitting breathability through the non-adhesive regions, thus resolving the contradiction between adhesion and breathability.
2Device complexity
If conventional pattern coating methods (screen printing or slot coating) are used with silicone adhesive precursor, then manufacturing complexity is reduced, but the viscous solvent-free precursor cannot be properly applied
Solution Approach 1:
The invention changes the physical parameters of the coating system by using larger aperture sizes in the mesh screen compared to conventional screen printing. This parameter change allows the viscous solvent-free silicone precursor to be successfully applied through the screen, overcoming the viscosity issue while maintaining the simplicity of the screen printing process.
3Device complexity
If silicone adhesive is applied directly to hydrophilic wound dressing materials, then manufacturing steps are reduced, but adhesion is weak without a primer coating
Solution Approach 1:
The invention applies local quality by creating discrete patterned regions of silicone adhesive on the hydrophilic substrate. The patterned application ensures that adhesive is placed only where needed, achieving sufficient adhesion strength at the adhesive-substrate interface without requiring a primer layer, while maintaining the simplicity of direct application.
4Manufacturing precision
If the aperture size in the mesh screen is kept conventional, then manufacturing precision is maintained, but the viscous silicone precursor cannot pass through
Solution Approach 1:
The invention changes the aperture size parameter of the mesh screen from conventional dimensions to larger dimensions. This parameter change enables the viscous silicone precursor to flow through the screen during pattern coating while still maintaining sufficient manufacturing precision to create accurate adhesive patterns on the substrate.
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 method achieves a patterned silicone adhesive coating that enhances breathability of wound dressings by allowing moisture vapor transmission while ensuring strong adhesion to hydrophilic surfaces, improving the compatibility and performance of silicone adhesives in medical applications.
Implementation Method 1
followed by thermally curing the precursor composition coated on the substrate
Implementation Method 2
pattern coating a silicone precursor composition onto the substrate by the steps of coating the silicone prepolymer composition onto an apertured support layer having holes and lands
Implementation Method 3
enhances breathability of wound dressings by allowing moisture vapor transmission
Data Source
AI summary
A method of applying a patterned coating of a silicone adhesive to a substrate sheet, comprising the steps of pattern coating a silicone precursor composition onto the substrate, followed by thermally curing the precursor composition coated on the substrate. The precursor composition is a viscous fluid, and the pattern coating is performed by suitably modified block printing, intaglio printing or screen printing methods. Also provided are coated substrates obtainable by the methods of the invention, and wound dressings comprising such coated substrates.