In today’s elastomer market, the choice of rubbers available to engineers and designers is vast. The sheer number of choices can often cause confusion as to which rubber to select for certain applications. Properties such as temperature resistance, compression set, tear strength and elongation may not be fully understood, which therefore effects making the correct choice of rubber.
Here we discuss why engineers choose silicone rubber as a material over other rubbers and the benefits the elastomer has when in application.
Firstly we must outline that all rubbers have both positives and negatives depending on application conditions and as of yet, there is not one rubber that ‘ticks all the boxes’. So this leaves us with the realistic conclusion that we must delve deeper into the application conditions where the rubber will eventually be used to gain a better understanding of the stresses the material will face before giving a professional opinion.
As we’re a silicone rubber manufacturer we consider ourselves experts in the HCR silicone arena and hold a vast amount of knowledge which has been built up over the last 55 years.
So let’s discuss below the most common properties of silicone to allow you to understand why engineers choose the material.
Silicone is most commonly associated with its excellent resistance to extreme temperatures and this is generally one of the primary reasons silicone gets selected for application. Unlike the majority of other elastomers, silicone can withstand temperatures in excess of 230°C (446°F). When compared to EPDM which can only reach a maximum of 150°C (300°F), you can see why silicone is the elastomer of choice in applications that experience extreme heat. On the other side of the thermometer, silicone can also withstand temperatures as low as -60°C (-76°F) which means, unlike other elastomers that go brittle, silicone stays flexible in extremely cold conditions.
We discussed temperature resistance in one of our recent blog posts as it is often a topic that causes some debate relating to the maximum/minimum temperatures that silicone can withstand.
Some silicone rubber datasheets state that silicone can withstand maximum temperatures of +300°C (572°) which looks impressive however, we know that silicone exposed to this constant temperature will last a matter of minutes, which is not always explained on datasheets. It is true however that silicone can withstand 300°C but this would be for short intermittent periods and is something that should be indicated to prevent failure in application.
Our silicone grades can withstand consistent temperatures of 230°C (446°F) which in most cases is suffice in many high temperature applications. We also have our high temperature grade THT that can achieve a constant 270°C.
Silicone rubber has excellent resistance to environmental conditions, making it the ideal material to be used for outdoor sealing applications that may be exposed to the elements. Silicone can withstand Ozone and UV stresses which allows the material to maintain its original properties and prevent degradation.
Silicone also has excellent resistance against general weathering from rain, sleet, snow and frost allowing protection to electrical enclosures situated outdoors.
Low Compression Set
Another benefit of silicone (silicone sponge in particular) is low compression set. Meaning that if the silicone is under compression for a length of time, it recovers and maintains its original shape. This is generally linked to a seal or gasket application that is often compressed, usually a door or enclosure that needs pressure applied to form a good seal. Once that door or enclosure is opened again the seal should return to its original shape and not become deformed.
To read an in-depth report on compression set, go to one of our blog posts where we explain in detail ‘why compression set is so important in the sealing world?’
Silicone is an inert polymer, meaning that it is mainly non-reactive. This makes it the go to elastomer in the food and beverage industry as it little to no effect on the products themselves. From dairy tubing to brewery hoses, Silicone Engineering’s silicone is widely used on a global scale. It is approved to FDA, BfR and WRAS standards which allow it to be in contact with food or beverages without causing contamination. Go to our Food & Beverage page to read more.
These are just some of the many benefits silicone rubber can bring to applications when other elastomers fail. Silicone can resolve and/or prevent a number of sealing issues, which can increase the lifespan of a seal and also reduce replacement costs.
If you require any further information on our silicone rubber products, get in touch by clicking the link below.