Why You Should Know Silicone Rubbers

Both of organic silicone products and inorganic silicone matters play important roles in today’s chemistry world. In today’s organic world, silicone rubbers are also pretty welcomed by many industries rather than the usual silicone oil liquids. 

Silicone-Rubber Made Balloons (Cited from: https://pixabay.com/zh/photos/rubber-balloons-colorful-decoration-6003203/)

(Cover Photo Cited from: https://pixabay.com/de/photos/ballons-bunt-schwimmbad-wasser-1761634/)

What Is Silicone Rubber

Silicone rubbers is also called OH Terminated Polydimethylsiloxane which comes from its chemical structure and some chemical characteristics. This is similar with silicone oils, which are also named as dimethicone oil or polydimethylsiloxane liquid. Silicone rubber is one of the largest productions among all of silicone products. It is also one of the widest applied silicone liquid products. After vulcanization, silicone rubbers will have excellent chemical and physical features like heating resistance, cold resistance, isolation and stability. These good characteristics allow silicone rubbers to be used widely in national defense, medical care and industrial & agricultural productions.

Silicone rubber high polymer numerator is in the chain form which is structured by Si-O key. Its main components are linear polyorganosiloxane who have high mols. It is due to the chemical key of Si-O-Si is the basic structural key of silicone rubber numerators, silicone rubbers have better heating resistance, isolation and chemical stability than other rubbers.

Silicone rubbers are always in the form of colorless transparent liquid, it is non-toxic and pretty stable under normal conditions.

As for its heating resistance, the silicone rubber could be used normally under 150 Celsius degrees without any changes on capacities; It could be used in ten thousand hours continuously under an environment of 200 Celsius degrees; It could also be used in a long time in the heated environment which is 350 Celsius degrees. Thus, it is widely used in the products which will directly touch high-temperature environment such hot water bottle, handles of some devices of steel manufacturing and other relevant fields.

Silicone rubbers also have high isolations of electricity. Their electrical resistivity is pretty high and it could maintain status quo during a wide range of temperature and frequencies. It is then applied in many electrical devices and even the corresponding cables.

Silicone rubbers could be ignited. However, when add some add-on chemicals, silicone rubbers will have good fire resistance. Even if the rubbers are being on fire, there will be no poisoned gas to be produced due to the silicones are non-toxic and they have no smells.

Silicone rubbers also have good radiation resistance. Some nuclear industries (like electricity suppliers) use silicone rubbers to avoid the spread of nuclear radiations.

The rubbers are famous for being breathable as well. It also has a good selective characteristic to some special types of gases. This allows silicone rubbers to be used in medical devices like artificial organs or medical silicone tubes.

Applications of Silicone Rubbers

Typically, silicone rubbers’ applications could be divided to two categories according to the vulcanization temperatures. These two categories are high temperature vulcanized type (HTV) and room temperature vulcanized type (RTV). The former category is mainly aimed at producing normal silicone rubber products, while the latter category is used for making molds, add-on chemicals and other chemical liquids.

The first type (HTV) is the most important type of silicone rubbers in today’s organic silicone products. VMQ is the most common subcategory of it, which is usually named as high-temperature glue. VMQ is colorless, non-toxic, non-smelly, non-impurity jelly. It is usually been processed with thickeners and other chemicals to be shaped into the final matured products. It has high electrical isolation, waterproof, pressure reduction, stability and breathability. It is mainly applied in aerospace, tablets, electronical devices, shipping, mechanics, automotive and medical care industries. It could be shaped into sealing circles, pads, tubes and electrical cables in any forms customers want. It could also be used for artificial organs or blood tubes, breathable covers and rubber molds (like LSR silicone rubber molding).

The second type is the RTV, it has two subcategories which are condensation type and additive type:

Condensation type has two main products- RTV-1 and RTV-2. RTV1 glue could be used in a long time during the temperature range from -60 Celsius degrees to 200 Celsius degrees. It has excellent electricity isolation, chemically stability, waterproof, and good connective ability to many metal and non-metal materials. RTV-1s are mainly used in the painting of some electronical components and some electrical devices, the sealing material of some products due to its high isolation capacity; or be as the covering materials of semi-conductor devices; Sometimes they are also being used for the filling materials or glues. RTV-2 is not as directly useful to compare with RTV-1. However, the structure of RTV-2 is more varied than RTV-1, which means one type of RTV-2 could have many different specifications of vulcanized products. RTV-2 could be also deeply vulcanized. This is why RTV-2 is widely used in automotive, machines, constructions, textiles, chemical and printing industries due to its wonderful isolation and sealing ability.

Additive type’s silicone rubber has the feature of heating resistance, waterproof and electrical isolation. It also has excellent mechanical features which are the evidently increment of its tensile strength and tear strength.

Another typical application of organic silicone rubber or RTVs is in the decorations & accessories of houses. One example is the glass curtain wall which is made by glass and aluminum alloy structure with using silicone rubber as the glue to connect them while the sealing parts are also filled by silicone rubber glues. The other aspects of applications include the sealing of aluminum alloy doors & windows and plastic steel doors & windows, the sealing parts of the inner glasses of windows, the waterproof sealing of parts in the bathrooms, the sealings of the roofs of workshops and aquariums. Besides family-use glues. RTVs are also widely applied as the sealing glue of aerospace, nuclear power stations, electronical and automotive industries. Even though the requirement of silicone rubber glues is small but they are essential.

Summary

It is since Dow Corning has developed new methods of producing organic silicone products in 1943, after the development over half a century, now the world’s silicone rubber market is shared by few multinational companies like DC, GE, R-P, Wacker and ShinEtsu. There are more than 10 corporations who are majoring in manufacturing and selling organic silicone products and today there are more than 5,000 types of organic silicone products with the rapid increments of their productions and amounts of sales. In the recent 30 years, the annual increment rate of industrial organic silicone products maintains between 8%~15%.

This is why we should know more about silicone rubbers since they are more and more closed to our everyday life and the market of them is large and the future is bright.