What Is Silicone Resin?
Silicone resins are resins whose main backbone is a siloxane bond (Si-O-Si) composed of silicon and oxygen and are also commonly referred to as silicone. Organic groups are introduced into the side chains, and silicone resins exhibit both inorganic and organic properties. They also exhibit various physical properties depending on the type of functional group in the side chain.
Siloxane bonds have higher bonding energy than the carbon-carbon bonds that form the main chain of plastics, so silicone resins have better heat resistance, weather resistance, and electrical insulation properties than general plastics.
Silicone resin is classified into silicon oil and silicon rubber. In the case of liquid silicone resin, injection molding, and extrusion molding are used to mold it as a product. Recently, 3D printers have also been used for molding.
Uses of Silicone Resin
Silicone resin is a resin consisting of silicon and oxygen repeatedly bonded together. It is used as silicone oil or silicone rubber, taking advantage of its various advantages such as heat resistance, weather resistance, and electrical insulation.
For example, it is used as a heat-transfer medium as a highly heat-resistant oil, or in industrial applications such as anti-vibration oil in environments with extreme temperature changes. It is also used in other applications such as baby bottle rubber, various gaskets, and shampoo.
In the construction field, it is also used as a protectant to prevent the deterioration of coatings and gaskets. Silicone resin is also used in various parts of vehicles.
Principles of Silicone Resin
Siloxane bonds, which are continuous silicon and oxygen bonds formed in silicone resins, belong to the same class of inorganic materials such as glass and quartz. Siloxane bonds have higher bonding energy and are chemically more stable than carbon-carbon bonds, which are the main type of bonds in organic materials. This is one of the reasons why silicone resins have high heat and weather resistance.
Siloxane bonds exhibit inorganic properties, whereas silicone resin also has organic functional groups such as carbon in the side chain, so it exhibits both inorganic and organic properties. In addition, various organic functional groups such as methyl groups, alkoxy groups, and amino groups can be introduced into the side chain, and different properties can be expressed depending on the functional group. For example, silicone resin with three or more oxygen groups bonded to silicon exhibits a three-dimensional network structure and exhibits particularly excellent heat resistance and weather resistance.
Difference Between Silicone Resin and Plastic
Although silicone resins are highly processable and have characteristics similar to plastics, such as softening upon heating, they are chemically different substances. Silicon resins contain a large number of silicon atoms in their main backbone, whereas plastics such as epoxy resins have the main chain backbone composed primarily of carbon atoms.
Compared to the carbon-carbon bonds in the main skeleton of plastics, the bonding energy of the silicon-oxygen bonds in the main skeleton of silicone resins is higher and less reactive, so they generally have better chemical and heat resistance than plastics. For this reason, silicone resins are widely used in daily necessities, kitchenware, and industrial products. However, care must be taken when using chemicals, as contact with strong acids and alkalis can cause decomposition and degradation.
Safety of Silicone Resin
Silicone resin has extremely low physiological activity and is considered to have virtually no effect on the human body. It also has low health effects even if ingested orally, and studies on acute toxicity and genotoxicity have been reported to be negative.
Silicone resin is used in tableware and cooking utensils, etc. It is an extremely stable resin and does not react with food even in high-temperature environments during cooking. However, if the temperature reaches an abnormally high level due to overheating or emptying, the silicone resin may melt or discolor, so care must be taken when using it at high temperatures.
On the other hand, silicone resin contained in sprays is a very small particle that can cause respiratory poisoning if inhaled. Even when using household products such as water-repellent sprays, care must be taken in handling them, such as using them in a well-ventilated area and not using them directly on the human body. In addition, instructions and Safety Data Sheets (SDS) should be carefully read before use.