These are the ranges of actual materials with silicone contents. The materials are in the form of :

• Primers
• Adhesives
• Coatings and Sealants
• Fluids and Greases
• Foams
• Resins
• Gels
• Fluorosilicones
• High Consistency Elastomers
• Liquid Silicone Rubber
• Controlled Volatility

The device manufacturers choose depending on :

• Function of the Devices
• Process Requirements
• Physical Properties
• Regulatory Issues

Choosing the Right Silicone

• What is the intended use or function of the silicone?
  – Adhesive
  – Extruded tubing
  – Lubricant
• What are the Process limitations /requirements?
  – Cure conditions / environment
  – Viscosity / Rheology
  – Process time / yield requirements
• What are the cured physical property requirements?
• What properties should be tested?
• Regulatory issues? Application? Industry?

Adhesives & Sealants

• Definition: Silicone adhesives are widely used to bond silicones to other materials such as metals, thermoplastics, ceramics, and urethanes. These products can be formulated into both one-part and two-part systems. All one-part systems require atmospheric moisture to cure, two-part systems can employ either moisture-or platinum-curing agent.

• Process: Dispensing guns

• Examples:
  – MED-1137: Non-slump
  – MED-2000: Self-leveling
  – MED-1511: Flowable
  – MED1-4213 / MED2-4213: Fast cure platinum catalyzed adhesive.
• MED-1356: Pressure sensitive adhesive. For topical use only.

Silicone Coatings

• Definition: A silicone coating is typically a low viscosity material used to provide a protective barrier to a surrounding environment. Silicone coatings can be either low consistency elastomer systems or silicone dispersions.

• Process : Silicone coatings may be applied by dipping, spraying, or wiping.

• Examples:
  – MED10-4161: One-part, curable lubricious coating.

• Applications:
  – Coatings for needles
  – Trochars
  – Catheters
  – Applications requiring reduced surface tackiness
  – Siliconization.

LSR: Liquid Silicone Rubbers

• Liquid Silicone Rubbers (LSRs) are 2-part, platinum-cure silicones of intermediate viscosity, which allows them to be pumped through liquid injection molding (LIM) equipment using airless mixing/metering equipment.

• Durometer ranging from 5 to 85 Type ‘A’

• The advantage to such a molding system is reduced parts costs through rapid automation of the molding operation and the formation of a flashless part.

• Cure is typically achieved at 2- 5 minute cycle times at 150°C

• Unrestricted products are designated as MED-48xx and restricted products as MED-49xx, where the last two digits comprise Type A durometer

Duck Bill Valve

• Materials:
  – MED1-4955
  – Self lube LSR
• Eliminates the need to lubricate

HCR: High Consistency Rubbers

• Definition: HCR consists of a high molecular weight polymer combined with silica. They must be worked on a 2-roll mill for mixing and freshening. They are primarily formulated in a one or two part system (peroxide and platinum catalyst).

• Durometer ranges from 20 to 80 Type A.
  – Peroxide materials are often chosen because they can be pre-catalyzed
  – Have virtually unlimited shelf life and give lower tensile and compression sets.

Healthcare Applicants

Balloons: For Foley Catheters, Urinary Applications

• Materials:
  – MED-4025
  – MED-4128
• Benefits:
  – Excellent recovery

LCE: Low Consistency Elastomers

• Definition: Very versatile group of elastomers. Flowable viscosities and strength allow for potting compounds, molding, coatings. Low consistency elastomers are available with addition (platinum) or condensation (tin) cure systems

• Examples:
  – MED-4211: Two part / platinum cure / pourable system
  – MED-6219: Low viscosity / high durometer
• Optically clear silicones: Resin reinforced elastomer systems.

Healthcare Applicants

Intraocular Lenses or Lens Devices

• Materials:
  – MED-6820
  – MED-6233
• Benefits:
  – Optically Clear

Colored Silicones

• Palette of eight colors, white, black, light and dark blue, green, yellow, orange and red

• Restricted and Unrestricted product lines available

• Tested to Class VI and many ISO 10993 Biological Testing Requirements

• Submission of Master Access File to U.S.FDA

• Color matching available

Summary

• Silicones have a long history of use in Medical & Drug Delivery Devices

• There are many regulatory and testing requirements to consider

• Many material options for the device designer

• NuSil committed to the Healthcare Industry