Specialty Elastomers A

Each elastomer is supplied as a two-part kit (Part A and Part B), equal portions of which must be thoroughly blended together prior to use. The elastomer is thermally cured via an addition-cure (platinumcatalyzed) reaction. When blended and cured as indicated, the resulting elastomer consists of crosslinked dimethyl and methyl-vinyl siloxane copolymers and reinforcing silica. The elastomers are available in a range of nominal hardness from 30 to 70, Durometer-Shore A. The elastomers can be used without any post-cure although if necessary, this may be employed to stabilize final properties. Furthermore, the elastomers are heat stable up to 200°C, can be autoclaved, and exhibit high gas permeability compared with most thermoset elastomers and thermoplastics.

Features

• Contains no peroxides, peroxide byproducts, chlorophenyls or PCB
• No organic plasticizers, phthalates or latex additives
• Solventless
• Non-blooming
• Can be post-cured

Benefits

• United States Pharmacopeia (USP) Class VI, European Pharmacopeia (Ph. Eur. or EP ) Silicone Elastomers for Closures and Tubing- Substances soluble in hexane and Volatile matter, ISO 10993-1 Surface devices: cytotoxicity, sensitization and irritation/intracutaneous reactivity,
• Fast cure system
• Easy processing
• Batch-to-batch consistency
• Cost-effective.
   

Specialty Elastomers A are platinum-catalyzed materials designed for part fabrication and medical devices, including those intended for implantation in humans for up to 29 days.

These elastomers are supplied as twocomponent kits (Parts A and B) that must be thoroughly mixed in equal portions, by weight, prior to use. Airless mixing, metering and dispensing equipment are recommended for production operations. Information is available from DuPont on the suppliers of suitable pumping, mixing, and molding equipment. If hand mixing, a vacuum of 711 to 737mm Hg should be sufficient to de-air the material in 20 to 30 minutes. Use a container 3-4 times the volume of the mixture to allow for expansion.

Cure: Cure of the mixed elastomer is accelerated by heat. Raising the temperature of the mixed material to 110°C results in a rapid cure to a tough, elastomeric material. Please note that mixing parts A & B at anything other that a 1:1 ration, by weight, will likey change the molding times, and the resulting material's properties.

CAUTION: The cure may be inhibited by traces of amines, sulfur, nitrogen oxide, organotin compounds and carbon monoxide. Because organic rubbers often contain these substances, they should not come in contact with the uncured elastomer. Catalyst residues from some room temperature vulcanized and peroxide-cured silicone elastomers may also inhibit the cure.

Post-curing: These materials crosslink via an addition-cure (platinum-catalyzed) reaction. No organic residues such as peroxides or their by-products are present and post-cure is not normally required for most applications. The user must confirm that quick molding or short oven cures are suitable for any specific application. The principal volatile components evolved during post-curing are low molecular weight polydimethylsiloxanes and water vapor.

Specialty Elastomers A are supplied in 36kg and 400kg kits, containing equal portions each of Parts A and B.