Everyone knows silicone from the medical world, but it is also extremely suitable as a sealing material. Silicone seals are the right choice if a plastic or coloured seal is required at high temperatures. This is by definition a static application. Silicone materials can easily withstand standard environmental conditions and can also be divided into two main groups: with a focus on heat resistance or with a focus on chemical resistance. Once you know which property is important for your application, NDS-Seals can advise you on the material to be used.
In addition to heat and chemical resistance, silicone seals have some other advantageous properties. For example, the material can easily be made suitable for applications in the food industry. In this article we extensively explain the advantages and applications of silicone seals. Would you prefer direct advice from the experts at NDS-Seals? Then please fill in the form below.
Heat and chemical resistance of silicone
The quality of the silicone seal is determined by the composition of the raw materials. As with other elastomers, this differs per market segment. This means that the seal functions optimally for the respective application. For hot air applications, for example, a high heat resistance is required. Silicones can be used at particularly high temperatures (up to 275°C). For other applications, however, increased chemical resistance is required, e.g. in boilers or in the process industry.
Applications of silicone seals
Previously, metal was more often used as a construction material. Nowadays more and more people work with plastic, because it is much lighter and often cheaper. A disadvantage of plastic, however, is that it is usually less stiff by itself. Moreover, plastic expands or shrinks with temperature changes. To prevent the seal from crushing the construction when the material deforms, plastic seals with a low hardness must be used in many plastic constructions. Silicone is ideally suited for this purpose. No other elastomer is as plastic as silicone. In addition, silicone seals can be produced in low hardnesses, without detracting too much from the quality of the seal.
Mechanical engineering and HVAC
Plastic seals are not only desirable in plastics. This type of seal is also widely used in electronics. Large markets for silicone seals are mechanical engineering and HVAC (heating, ventilation and air conditioning). More and more constructions are electronically controlled. These controls must be properly sealed so that they remain free of moisture and dust. Because constructions are generally becoming smaller and lighter, easily deformable seals with a small geometry are required. In other words, plastic seals with a low hardness are required: i.e. silicone. With click connections in the plastic constructions, silicone seals are easy to install in the small installation spaces of electronic controls.
Silicone seals are also often used in the food industry. Silicones can easily be made suitable for applications in the food industry, unlike many other elastomers. Other elastomers are only used for dynamic applications in the food industry.
Silicone seals: easy to colour
Silicones are ideally suited for producing coloured seals. The material can be made in all conceivable RAL colours because the base material is transparent. Moreover, this makes silicone the only material that can be used to produce transparent seals. Silicone seals are in this respect the maverick among rubber seals. Silicones are composed of silicon oxygen compounds in the base, while other rubbers are hydrocarbon compounds (collectively referred to as elastomers). In fact, silicones are not rubber but plastic.
Special production lines for silicone seals
Rubbers are black in the base, which makes them difficult to colour. For example, if you want to make a pot of black paint bright yellow, you will need a huge amount of yellow paint and even then the colour will have a dull look. The same problem exists when colouring synthetic rubbers. Silicones, on the other hand, can easily be coloured with pigment. NDS-Seals uses special production lines for silicone seals to prevent contamination. If a machine still contains remnants of a black elastomer, this is immediately visible in the coloured or transparent product.
The advantages of coloured seals
Coloured seals are often used to create a certain recognisability. Branding, for example, can be a goal here. Coloured seals are also used for practical reasons. Internationally, for example, the same colours are used for the seals of cold water pipes (blue), hot water pipes (red) and gas pipes (yellow), often in the form of a grommet. Transparent seals are usually used for aesthetic reasons. For example, you can use transparent silicone for the seals of a transparent water tank, so that the construction is visually attractive.