Momentive (Leverkusen, Germany) chose the Fakuma trade show in Germany this week to launch a new liquid silicone rubber formulation in its Silopren portfolio of materials that helps to solve a sticky problem for medical device manufacturers, among others. Silopren LSR RSH significantly reduces so-called self healing in silicone rubber valve slits, which can cause the opening to partially or fully seal shut. Mini-valves and multi-slit designs are prone to this, according to Momentive, and it can be especially problematic in medical device applications, as this can lead to dosing variances and even device failure in needle-free infusion systems, for example.
“The valve can stick when exposed to harsh conditions,” Tina Wei, Global Marketing Director, Life Science, told PlasticsToday from the Momentive booth. “This can occur during storage or special processing. In the past, self-healing has been addressed by applying a non-stick surface treatment to the part or adding release agents or oils to the material,” adds Wei, “but those processes increase the risk of contamination.” They also may increase the cost to manufacturers.
The Silopren LSR RSH series minimizes the self-healing property of silicone rubber without the use of additional processing steps, additives or surface treatments. In addition to a number of desirable physical properties, the material resists aging, withstands exposure to oils and chemicals and can be gamma sterilized. Applications include a range of valve and fluid flow parts in the medical, infant care and food sectors.
Research on the material took the better part of a year, says Wei, which included internal validation as well as external validation by customers. Silopren LSR RSH is available in 40 and 50 Shore A; other hardnesses can also be dialed in on a custom basis.
“Momentive is dedicated to solving customer problems, and this is just our newest example of how we address customer issues and add value,” adds Wei.
The international plastics trade fair Fakuma runs through Oct. 17 in Friedrichshafen, Germany.