Liquid silicone injection molding: advantages and properties
Silicones are materials of a polymeric nature, formed by an alternating chain of silicon and oxygen atoms, they are good elastomers because the main chain is very flexible.
Its manufacture is based on radical addition vulcanization (HTV) and, thanks to its chemical structure, special technical and aesthetic results that are difficult to obtain with traditional products, are achieved. In addition, it can be sterilized by ethylene oxide and radiation.
Liquid silicone injection molding (LSR) has several advantages in the manufacture of silicone parts, most notably the speed and excellent finish of the products, although the design and machining of the molds is more complicated than thermoplastic injection molds.
The main properties of silicone are:
- Resistant to extreme temperatures (-60 °C to 180 °C permanently - up to 250 °C or higher for short periods of time).
- Elastic at low temperatures (below -100 °C as a static seal and in dynamic conditions down to -75 °C).
- Low permanent deformation, even at extremely low or high temperatures.
- Resistant to weathering, ozone, radiation and humidity.
- Hydrophobic characteristics, absorbing small amounts of water and evaporating quickly.
- Excellent electrical properties as an insulator, maintaining its dielectric properties when exposed to extreme temperatures that other materials would not withstand.
- High resistance to compression deformation
- Resistant to some chemicals, including some acids, chemical oxidizers, ammonia and isopropyl alcohol. Silicone swells when exposed to non-polar solvents such as benzene and toluene, returning to its original form when the solvent evaporates.
- Long shelf life.
- Biocompatible, suitable for food and sanitary use.
- Variety of hardnesses depending on the application of the part.
The characteristics of silicone are: flexibility and softness to the touch, it does not stain or wear out, it does not age, it does not exude (avoiding deterioration and soiling, as well as corrosion on the materials that are in contact with it), has great resistance to all types of use, is non-polluting and can be widely colored.
At OSF we have the necessary technology for the injection of liquid silicone parts (LSR) in different sizes and adapting the material to the application and needs of our customers. We have an ISO-7 Clean Room to inject silicone parts in contaminant-free conditions for the medical, pharmaceutical and veterinary sectors.