Applied Silicone Corporation Implant Grade High Consistency Addition Cure Molding Systems HCRA(M) are two part platinum catalyzed silicone elastomers designed for use in processes where high strength molded parts are desired. This material is specially formulated for a long potlife and a molding cure profile.  HCRA(M) contains 100% by weight of dimethyl silicone elastomer when cured. This product is supplied in two components consisting of equal amounts of Part A and Part B which are strained through a 400 mesh (25 micron) screen to ensure freedom from particulate contamination. 

The stringent biocompatibility requirements imposed upon these materials make this series of elastomers ideally suited for use in critical medical devices. Custom formulation for radiopacity, color, etc. is available upon request. Important characteristics include:

• Long mixed life for molding applications
• Blendable to modify durometer
• No volatile cure by-products
• Optional post cure
• Non-tacky surface
• Non-blooming
• No peroxide residues
• Tested under FDA protocol as a substitute to replace discontinued Dow Corning Medical Grade Silicone for long term implantation. 

FDA Master File references including formulation, manufacturing methods, testing and toxicology are available.

Applied Silicone Implant Molding Grade HCRA(M) High Consistency Addition Cure Silicone Elastomer Systems are designed to be mixed in equal parts using standard rubber processing techniques such as two roll milling. Care must be taken to work in a clean area with clean equipment, as traces of foreign materials can poison the catalyst, and inhibit  the cure. For optimum results, freshen both parts separately on a two roll mill before mixing them. Do not allow material temperature to exceed 30ºC during milling.  Mixed material should be used within twenty-four hours to prevent structuring and premature crosslinking. Store mixed material in a freezer to extend the working time. Cure is typically achieved in three minutes at 150ºC. Post cure is recommended to stabilize physical properties. Typical postcure is one hour at 165ºC.
 

Accurate measuring and complete mixing are important factors in obtaining consistent results. Contamination by trace amounts of compounds containing sulfur, amines, and organometallic salts can result in an unreliable cure of the material. Organic rubbers and tin catalyzed silicones often contain compounds which can interfere with the cure of this material and should be avoided. HCRA(M) begins to cure in about eight hours at room temperature.  Mill components and use promptly for best results. Clean equipment thoroughly to avoid cured residue which may result in crumbs of  elastomer being picked up by the next lot  causing "gels" and imperfections. 

Mix only what is intended for use.  Mixed shelf life at room temperature is approximately twenty-four hours.  Mixed material can be stored at lower temperatures to extend pot life.  

Packaging is available in 50 pound kits. This material should be stored under cool and dry conditions.  Containers should be sealed to avoid contamination. 

Suggested retest is six months from the date of shipment. 

Each production lot is certified as having passed Cytotoxicity and physical properties. Other testing is available upon request. 

Revised 10.07.03