Biocompatible lubricants based on silicone are used to lower the friction between components in medical applications or between a component and skin. Lubricants from Nusil are biologically tested according to ISO 10993 and have FDA masterfiles.
Silicones are effective lubricants thanks to their long, linear polymer chains with high mobility. They are also resistant to oxidation, chemically inert as well as hydrophobic.
When you are trying to lower the friction of your medical component, the type of material, design of the component and the type of movement will contribute to your choice of lubricant.
Applications for biocompatible lubricants
- Reduce insertion force, e.g. for needles, cannulas, trocars and cutting tools.
- Reduce drag forces, e.g. for catheters, guidewires and cutting tools.
- Minimize break-loose force, eg. for valves and stopcocks.
- As a hydrohpbic coating, e.g. on the inside of syringe cylinders.
Types of biocompatible lubricants based on silicone
Biocompatible silicone fluids are available in a number of different viscosites. Higher viscoisty fluids will lubricate for longer than lower viscoisty fluids. You will also find both regular silicone fluids and fluorosilicone fluids as well as mixes of the two to be able to adapt them to different substrates and applications.
Silicone greases are thixotropic (non-flowing) formulations that have little or no migration. This si the reason they are usually chosen when the lubrication needs to last for longer periods of time and on specific locations. They can also seal under vacuum.
A silicone dispersion is a silicone diluted in solvent to achieve a lower viscosity. This helps to get a thinner and more even layer of lubricant applied on the detail compared to un-diluted silicone fluids or greases.
A self-lubricating silicone is a silicone elastomer with built-in lubricant. The moulded silicone part will slowly and continually emit a small amount of lubricant from the silicone detail. This will reduce the tackiness as well as the friction of the silicone elastomer.
Common applications for self-lubricating silicone elastomers are injection moulding or compression moulding of valves, o-rings, seals and plugs.
Curable silicone coating
Curable coatings from Nusil that lower the coefficient of friction are applied to the surface of a silicone detail and cured there to lower the surface friction. This will prevent tackiness and friction of the silicone detail as well as increase the abrasion resistance of moving silicone parts. In tests, the coefficient of friction has been shown to decrease by up to 74 %. The products are solvent-based and can be applied through spraying, dipping or brushing on moulded silicone parts. Efter application, the coating is allowed to cure to a dry coating which ensures that it will not migrate.
Do you want to know more about Nusil’s selection of biocompatible lubricants? Get in touch!