LSR Vertical Single-Slide Liquid Silicone Rubber Injection Molding Machine

What Is Silicone Rubber?

Silicone rubber is a high-performance synthetic elastomer composed of silicone and other molecules (e.g., carbon, hydrogen, and oxygen). It is characterized by high viscosity and elasticity, as well as better abrasion resistance, chemical stability, insulating properties, heat and cold temperature resistance, and weatherability than organic rubber.

The exact properties of a given piece of silicone rubber depend on the material’s chemical composition and structure. However, some of the generally applicable characteristics are as follows:

· Operating temperature range: -100° C to 350° C (depending on the length of exposure) and in some cases can be formulated for higher temperature ranges.

· Weatherability: resistant to wind, rain, UV radiation, and ozone

· Moisture resistance: for extended periods with 1% water absorption (for cold, warm, and boiling water)

· Steam resistance: indefinitely (for unpressurized steam)

· Chemical resistance: oils, solvents, polar organic compounds, and diluted acidic or alkaline substances

· Electrical insulation: 1TΩ·m–100TΩ·m over a wide temperature range and frequency spectrum

· Thermal conductivity: 0.2 W/mΩ·K

· Compression set: consistent from -60° C to 250° C

· Tear strength: 9.8 kN/m

Types of Silicone Rubber

As indicated above, different silicone rubber formulations result in different material behaviors. These variations can be categorized in several ways, including by molecular structure and form.

The latter categorization method classifies silicone rubber by viscosity and processing method. The main types are:

· Solid Silicone Rubber: Solid silicone rubber—also sometimes called high-temperature vulcanized (HTV) rubber—has long chains of polymers with high molecular weight. It can be processed by conventional rubber processing methods.

· Liquid Silicone Rubber (LSR): LSR has shorter chains of polymers with lower molecular weight. It must be processed by specialized injection molding and extrusion methods.

· Room Temperature Vulcanized (RTV) Rubber: RTV rubber is a one- or two-component system that falls between very soft to medium on the material hardness scale. It is typically used for sealing, encapsulation, or potting applications.

Applications of Silicone Rubber

Due to its numerous advantageous properties, silicone rubber finds application in a wide range of industries, including, but not limited to, the following:

· Aerospace (e.g., space suit elements)

· Automotive (e.g., gaskets and seals)

· Construction (e.g., coatings and sealants)

· Electrical and electronics (e.g., adhesives and encapsulants)

· Food processing (e.g., food molds)

· Medical (e.g., medical instruments components such as seals, tubes, and valves)

· Recreation (e.g., goggles and mouthpieces)

Liquid Silicone Rubber vs. Solid Silicone Rubber

As mentioned above, silicone rubber is available in several variations, including in liquid and solid forms. Below we outline the main differences between the two materials:

· Liquid silicone rubber exhibits high fluidity. The parts and products manufactured from it are generally transparent, odorless, and safe for use in applications involving direct contact with food or the skin. However, they typically require the use of expensive specialized processing equipment.

· Solid silicone rubber exhibits low fluidity. It is cheaper to purchase and process than liquid silicone rubber as it can be used alongside conventional equipment.

Silicone rubber has proven itself to be an essential material across various industries due to its remarkable durability, flexibility, and resistance to extreme environmental conditions. Its versatility allows it to be used in everything from automotive components to medical devices and high-tech communication systems.