Processing and Manufacturing Techniques for Optically Clear Liquid Silicone Rubber

In the world of manufacturing and engineering, silicone is an extremely important material due to its versatility and durability. One of the most useful forms of silicone is liquid silicone rubber (LSR), which is used in many industries for a range of applications. However, when it comes to creating products that require high optical clarity, optically clear LSR (OC-LSR) is the material of choice.

OC-LSR is specially formulated to provide outstanding optical clarity and excellent physical and chemical properties. Its superior clarity combined with its ability to resist yellowing, fogging, and hazing make it the perfect material for creating high-quality optical components such as lenses, light guides, and displays. In this article, we will discuss the processing and manufacturing techniques for optically clear liquid silicone rubber.


The formulation of OC-LSR is key to achieving the required optical properties. It is typically a two-part system consisting of a liquid base and a curing agent. The base is made up of a mix of dimethyl siloxane, phenylmethyl siloxane, and silica, which gives it its clarity and strength. The curing agent, on the other hand, is typically platinum-based and allows the base to cure at a controlled pace.

The formulation of OC-LSR can be customized depending on the specific application. For example, if it is being used for medical devices, it can be made to be biocompatible and meet ISO 10993 standards. Conversely, if it is being used for industrial products, it may need to be able to withstand high temperatures, UV radiation, or chemicals.

Injection molding

Injection molding is the preferred method for manufacturing OC-LSR components due to its ability to produce high volumes of parts with tight tolerances and complex geometries. The process involves the injection of the uncured OC-LSR into a mold cavity where it is heated and cured. The finished product is then ejected from the mold.

One of the key factors in injection molding OC-LSR is controlling the temperature and pressure of the injection molding machine. It is critical to maintain a precise temperature and viscosity of the material to ensure that it fills the mold cavity correctly and cures properly. Molds themselves are also important as they must be designed to prevent any surface defects or contamination, which can affect the clarity of the final product.

Compression molding

Compression molding is an alternative to injection molding that is commonly used for low to medium production volumes. The process involves placing a pre-determined amount of the uncured OC-LSR in a mold enclosed by metal plates that are heated and pressed together. The pressure and heat cause the material to flow and cure, forming the final product.

Compression molding can be more time-consuming than injection molding, but it allows for greater design flexibility and can be useful for intricate parts that may require additional pressures applied to them. As with injection molding, temperature and pressure control are critical for achieving optimal results.

Optically clear liquid silicone rubber is a highly specialized material that requires careful formulation and processing to achieve its superior optical clarity and physical properties. Injection molding and compression molding are the preferred methods for manufacturing OC-LSR components, with each offering unique advantages depending on the specific application.

Whether you are creating medical devices, optical lenses, or display screens, optically clear liquid silicone rubber is an essential material that can provide superior performance and clarity. By working with a knowledgeable manufacturer, like genvan, who understands the complex formulation and processing techniques required for OC-LSR, you can create high-quality products that meet the rigorous demands of today's industries.