Crosslinked Organopolysiloxane Coating for Syringe Sticktion
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Solution Overview
Problem
Existing coating systems for medical devices, such as syringe assemblies, face challenges with high breakout and breakloose forces, leading to sudden surges and inaccurate liquid dispensing, due to friction issues between surfaces, which conventional lubricants like hydrocarbon oils and silicone oils fail to adequately address.
Innovation Solution
A coating system comprising a combination of curable organopolysiloxanes with alkenyl and polar groups, applied to the surfaces of medical devices, which reduces friction forces by forming a crosslinked coating that is cured using irradiation, thereby minimizing breakout and sustaining forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional lubricants like hydrocarbon oils or silicone oils are applied to reduce friction, then breakout and breakloose forces are reduced, but the lubricants migrate from the surface to the surface interface over time, causing breakout force to increase during parking
Solution Approach 1:
The patent changes the chemical and physical parameters of the lubricating coating by using a crosslinkable composition that forms a cured coating. This transformation from uncured to cured state fundamentally alters the lubricant's properties, making it non-migrating while maintaining low breakout force. The crosslinked network structure prevents the lubricant molecules from migrating to the surface interface over time.
Solution Approach 2:
The patent employs a composite coating system comprising multiple components: a base polymer, lubricant, crosslinking agent, and initiator. This composite structure combines the lubricating properties of oils with the structural stability of crosslinked polymers, creating a coating that both reduces friction and resists migration during storage.
2Ease of operation
If a lubricating coating is applied to reduce friction, then smooth sliding contact is achieved, but the coating must remain stable and non-migrating during storage
Solution Approach 1:
The patent applies the lubricating coating in an uncured state that provides immediate lubrication, then cures it to lock the lubricant in place. This preliminary application followed by curing ensures both initial sliding smoothness and long-term stability during storage, preventing the migration problems that plague conventional lubricants.
Solution Approach 2:
The curing process fundamentally changes the physical and chemical parameters of the coating matrix, transitioning from a migratory liquid or soft film to a stable crosslinked network. This parameter change maintains the lubricating function while eliminating the migration issue, ensuring reliability during storage.
3Force
If hydrocarbon oils are used as lubricants, then breakout force is reduced, but the lubricants are soluble in various fluids and subject to air oxidation causing viscosity changes and color development
Solution Approach 1:
The patent creates a composite coating where conventional hydrocarbon lubricants are embedded within a crosslinkable polymer matrix. This composite structure provides the low breakout force of hydrocarbon oils while the crosslinked polymer network protects against solubility issues and oxidation, preventing viscosity changes and color development during storage.
Solution Approach 2:
The crosslinkable coating acts as an intermediary between the lubricant and the environment. It provides a protective barrier that prevents direct contact between the hydrocarbon lubricant and oxidizing agents or solvents, thereby maintaining lubricant stability while preserving the low friction benefits.
4Force
If polytetrafluoroethylene surfaces are used to reduce breakout forces, then friction is reduced, but the material is very expensive and the approach has not been totally effective
Solution Approach 1:
The patent changes the surface properties by applying a crosslinked lubricating coating that provides low friction comparable to PTFE but at much lower cost. The crosslinked structure ensures the coating's durability and non-migration, achieving the effectiveness needed to make this economical alternative viable.
Solution Approach 2:
The patent employs a cost-effective coating material that, while not as durable as PTFE, provides sufficient performance for the application lifecycle. The crosslinking enhances the coating's longevity, making this economical solution competitive with expensive PTFE surfaces.
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 coating system significantly reduces breakout and sustaining forces, enabling smooth sliding contact without sudden surges, allowing for precise and accurate liquid dispensing, even after storage, and reducing lubricant migration and viscosity changes.
Implementation Method 1
a coating system comprising a combination of curable organopolysiloxanes with alkenyl and polar groups, applied to the surfaces of medical devices, which reduces friction forces by forming a crosslinked coating that is cured using irradiation
Data Source
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AI summary
The present invention provides a coating system for an article including a first component having a surface in frictional engagement with a surface of a second component, wherein at least a portion of at least one surface of the component(s) is coated with a coating prepared from a composition including a first, curable organopolysiloxane comprising at least two alkenyl groups; and a second, curable organopolysiloxane comprising at least two polar groups, the second organopolysiloxane being different from the first organopolysiloxane, which can provide low breakloose force when used in syringe assemblies.