The versatility of liquid silicone rubber (LSR) allows it to be used across a wide range of industries and applications. In addition to providing design flexibility, LSRs also allow for high-volume production with low cycle times. The ability to combine LSR with resin substrates like copolyesters, such as Dow’s two new selective-adhesion LSRs, makes them ideal for use in medical device components designed to address respiratory issues or provide external communication capabilities.
Unlike compression molding, which requires the manual manipulation of a product, the process of liquid injection molding (LIM) offers a high level of automation and reduces the chance of contamination. A combination of heat and pressure then forces the cured silicone into the mold’s cavity, which can be closed to create complex parts in a variety of shapes and sizes. LIM also produces a wide range of finishes, including clear, translucent, opaque, and colored.
LSRs can be molded using the same equipment as thermoplastics, making it an ideal choice for companies looking to reduce time and costs while achieving higher-quality products. The ability to produce parts with tight tolerances can eliminate sink and rework, while a low linear shrinkage makes it easy to make accurate fit and finish parts. LSRs have a lower compression set than most thermoplastic elastomers, which can help reduce stress in the finished part and prevent warping or deformation over time.
These properties also make it a good choice for duplicating products that require undercut areas, such as bronze statues and plaster castings. Moreover, because of its relatively high hardness and good tensile and elongation properties, liquid silicone rubber can handle a great deal of stress without damage.
While the material can be used in a number of different applications, many manufacturers prefer to use it for industrial applications that require the highest levels of durability and optical clarity. These include automotive lighting and electronics, medical devices, and protective covers for electrical connectors. A high level of transparency and resistance to extreme temperatures also make it ideal for use in products that must withstand exposure to sunlight or other UV radiation.
The composition of silicone rubber can vary depending on the specific product, but all versions are made from silica, which is a compound of silicon and oxygen. Silica has the property of being able to absorb and retain a great deal of heat, which is a vital feature when working with high-temperature materials.
Liquid silicone rubber is often formulated to have a low compression set, which means that it will retain its elasticity even when subjected to constant strain over time. The low viscosity of the material also helps it to easily flow through a nozzle or injection tool for use.
The low odor and non-toxic nature of silicone rubber make it ideal for food and pharmaceutical applications, as well as for use in manufacturing components for medical devices and other sensitive products. For example, a medical-healthcare grade or Class VI silicone that has been tested for biocompatibility is suitable for menstrual cups, baby bottle nipples, and scuba mouthpieces.