For example, if the requirement is for a soft material (3 ° Shore A to 80 ° Shore A) to seal a device that might need to withstand autoclaving; silicone is the only material available.
Silicones possess excellent performance properties compared to other polymeric materials such as their ability to withstand a wider range of temperature extremes from -110C to 300C and high resistance to water and many other chemicals. Moreover, their high tear and tensile strength properties make silicones extremely flexible. Other salient features are that silicones are odourless, tasteless, bacterial resistant, and exhibit superior compatibility with human body. All these factors make silicones highly biocompatible when compared to other materials. Thus, there has been an increase in the application of silicones in the field of medical device fabrication.
Examples where silicones are used in medical devices are given below.
• Hospital / surgical - Wound dressings, devices, catheters, drains • Pharmaceutical - Fluid transfer & drug handling • Dialysis - Peritoneal & vascular access catheters • Enteral - Pump headers & feeding tubes • Drug Delivery - Hyper alimentation, & drug devices • Urological - Foley, drainage catheters • Cardiopulmonary - Oxygenated & access devices
One of the new ranges is the LSR 7000 series which is a family of highly transparent liquid silicone rubbers (LSR) offered in a range of hardnesses. The product is designed to be used in a 1:1 mix ratio, and typically cures rapidly to a high strength elastomer by heating in standard injection moulding equipment. The combination of outstanding optical properties coupled with the processing and productivity advantages of an addition-cured, platinum-catalyzed LSR, makes the LSR 7000 series an excellent candidate to consider for applications requiring enhanced optical transparency. Also, due to the excellent high temperature stability of silicone elastomers, the LSR 7000 series may be considered for applications where enhanced optical transparency is needed and potential stress cracking of thermoplastics is of concern.
Other new products are TP3293 which is used in scar management to keep the wound wet to promote faster healing and does not stick to the skin causing less trauma on removal. TP3904 is used traditionally as a stocking gripper and is also used to keep dressings in position. TP6209 is used as an adhesive to stick to the skin. Techsil also has a product called StatSil which is an antimicrobial elastomer for medical applications such as dressing coatings.
Another range which is proving very successful is the silicone gel series. These are generally used for pressure care providing shock absorption, pressure distribution and stability in items such as mattresses, wheelchair seats and cushions, orthopaedic liners and insoles.
Techsil's Sales Director, Chris Dilley says, "We are delighted that Momentive are focussing on medical materials in their R & D programme and are pleased with the interest already shown in these new products from the UK market."
About Techsil Techsil are industrial suppliers of RTV silicones, adhesives, sealants, encapsulants, conformal coatings, casting and mould making materials to a wide range of manufacturing industries across Europe including Aerospace, Automotive, Medical, Electronics, Film/Theatre/TV, Railway, Foundry and Rapid Prototyping.
Based in the UK and Germany, Techsil's success has led it to become the largest RTV silicone distribution partner in Europe for Momentive Performance Materials (formerly GE Bayer Silicone), Techsil are also suppliers of BJB polyurethane casting resins, ITW Devcon structural adhesives, ITW Permatex industrial bonding materials and Chemtrend mould release agents.
