Liquid silicone rubber (LSR) is a thermoset, vulcanized, and heat-cured elastomer that maintains its mechanical properties over a broad temperature range. This unique property makes it ideal for many applications in various industries. In the molded component industry, LSR can be used in a variety of ways to produce durable molded components for numerous applications. It is most commonly utilized in injection molding to create parts for products in a wide range of industries.
Liquid silicone is a low-viscosity polymer that can be easily injected into a mold cavity to create durable, pliable molded parts. It is available in a variety of hardness levels, and it can be pigmented to match a desired color. In addition, it is able to be overmolded with other materials to increase product functionality and design flexibility.
The primary ingredients of liquid silicone rubber are methyl and vinyl groups, which are polymerized to form polydimethylsiloxane chains. This chain structure gives the resulting material its ability to resist the effects of high and low temperatures, as well as provide physical stability. The raw uncured silicone looks and feels similar to clay. It can be formed into a stiff gum by adding reinforcing fillers, processing aids, and other additives. The resulting material can then be crosslinked via peroxides or polyaddition curing to create a solid silicone elastomer.
It is also possible to add antistatic, flame retardant, and antifungal additives into the liquid silicon. This allows the material to retain its integrity in harsh environments, which are often present in manufacturing processes and storage locations.
Unlike thermoplastic elastomers, liquid silicone can withstand extreme temperatures, making it the perfect material to use in automotive applications, as well as for outdoor and industrial equipment. It is also resistant to water, oxidation, and some chemical solutions, such as acids and alkalis. Liquid silicone can also be sterilized in a variety of methods, including steam autoclaving, ethylene oxide (ETO), gamma, and e-beam sterilization.
Injection molded parts made from liquid silicone rubber can be manufactured with complex shapes and thin features that would be difficult or impossible to achieve with a compression molded version of the same part. Its quick cure cycles mean that a single or two cavity injection mold can out-produce a compression mold of the same size, which reduces overall manufacturing time and costs.
LSRs can be cured using a combination of heat and pressure, which results in a strong bond between the material and the molded part. This eliminates the need for secondary operations like gluing and physical assembly, resulting in reduced production times and higher productivity. In addition, it provides excellent sealing properties that can withstand a variety of temperatures and fluid atmospheres. This versatility makes it a preferred choice of many manufacturers.