Liveo™ BioMedical Grade LSR Q7-4850

Each elastomer is supplied in a two-part kit (Part A and Part B), equal portions (by weight) of which must be thoroughly blended together prior to use. The elastomer is thermally cured via an addition-cure (platinum-catalyzed) reaction. When blended and cured as indicated, the resulting elastomer consists of cross-linked dimethyl and methyl-vinyl siloxane copolymers and reinforcing silica.

The Liveo™ QP1 LSRs are available in a range of nominal hardness from 30 to 60, Durometer-Shore A. The elastomers can be used without any post cure; although, if necessary, this may be employed to stabilise the final properties. Furthermore, the cured elastomers are heat stable up to 200°C, can be autoclaved, and exhibit high gas permeability compared with most thermoset elastomers and thermoplastics.

Liveo™ BioMedical Grade Liquid Silicone Rubbers (7-6830, 7-6840, Q7-4840, Q7-4850, 7-4860, 7-4870 and 7-6860) are heat-cured elastomer raw materials for use by customers fabricating medical devices, including those intended for implantation in humans for less than 30 days.

Qualified to address the tests described in ISO 10993-1 for "limited" (::24 hours) and "prolonged" (::30 days) contact duration: Meets or exceeds acceptance criteria for Cytotoxicity, Sensitization, Irritation/Intracutaneous reactivity, Systemic toxicity (acute) and Subchronic toxicity (as tested by implantation), Meets requirements of screening tests described by specific ISO standards for Hemocompatibility and Genotoxicity, Meets or exceeds testing requirements of: United States Pharmacopoeia (USP) Class VI, European Pharmacopoeia (Ph. Eur. or 'EP') silicone elastomers for closures and tubing-"Substances soluble in hexane" and "Volatile matter", Batch-to-batch consistency Contains no peroxides, peroxide by-products, chlorophenyls or PCBs, No organic plasticizers, phthalates or latex additives, Solventless, Non-blocking, Can be post-cured, Pigmentable.

MIXING:
Liveo™ BioMedical Grade Liquid Silicone Rubbers are supplied as two-component kits (Parts A and B), which must be 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 moulding equipment.

DE-AIRING:
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 initiated by heat. Raising the temperature of the fabrication to 140°C results in a rapid cure to a tough elastomeric material. Please note that mixing parts A and B at anything other than a 1:1 ratio will likely change the moulding 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 moulding conditions or short oven cures are suitable for any specific application. The principal volatile components evolved during post-curing are low molecular weight polydimethyl- silicone fluids and water vapour.

Liveo™ BioMedical Grade Liquid Silicone Rubbersare supplied in 36kg pail and 400kg drum kits, each containing equal portions of part A and B. Samples are available in 900g kits.