Advantages of Silicone Rubber Parts

Silicone rubber parts can be manufactured using either compression or injection molding. Both methods vulcanize the liquid silicone elastomer (LSR) into a mold cavity to create the final part.

LSR is usually mixed with a thixotropic agent to thicken it and an ultrafast catalyst to cure it quickly. These additives are essential to achieving quick cycle times for manufacturing.

High Temperature Resistance

High temperature resistance is a key feature of silicone rubber parts. Depending on the variant used, silicones can withstand temperatures between -150°C and +500°C without becoming brittle or melting.

This property, along with low stress relaxation and good elongation properties, allows silicone parts to remain flexible for long periods of time. It also enables them to return to nearly Silicone rubber parts 100% of their original dimensions after compression, making it easy to create seals that maintain their shape.

In addition to the above-mentioned components, the heat resistant silicone rubber compositions preferably contain reinforcing fillers such as silica fine powder; non-reinforcing fillers such as ground quartz, crystalline silica, diatomaceous earth and asbestos; metal oxides such as zinc oxide and aluminum oxide; and other additives including internal release agents, plasticizers and flame retardants. The curing agent may be a hydrosilylation reaction type organopolysiloxane and a photoinitiator; an acrylic functional polysiloxane and a photoinitiator; or a cation generating type catalyst and a photoinitiator.

High Flexibility

Like all elastomers, silicone rubbers start in liquid form and must undergo a polymerization reaction to create molecular chains. This is done to transform the LSR into a polydimethylsiloxane material. The resulting material can be molded into a wide variety of products by incorporating other functional groups, additives, and fillers.

Silicone rubber is used in many manufacturing industries because it is flexible and resistant to heat, cold, weather, and harsh chemicals. It also possesses low stress relaxation, which means that it can be stretched without becoming brittle or losing its original dimensions.

The flexibility of cured silicone rubber makes it ideal for compression and injection molding. In these processes, the raw silicone is placed into a mold that has been closed using a sealed clasping system and pressed under high pressure until it vulcanizes to the final product. This method of molding can be used to make everything from baby bottle nipples to medical catheters.

Low Stress Relaxation

Silicone rubber has low stress relaxation, meaning that it can maintain its original shape even after being compressed for extended periods of time. This makes it an ideal material for seals and closures that require memory.

Its high tensile strength and elongation at break also make silicone rubber an excellent choice for mechanical applications that require durability and flexibility. Silicone rubber can withstand temperatures from -150 to 550°F without becoming brittle or melting.

Observing how silicone rubber behaves under varying degrees of stress and strain can offer valuable insights into its lifespan. Laboratory experiments and computational models can provide a wealth of data, but Silicone rubber parts real-world testing over long periods of time provides the most comprehensive information. By incorporating design features that distribute mechanical stress evenly, such as curves instead of sharp corners, silicone rubber parts can avoid premature failure due to excessive strain. Also, by using proper draft angles and minimizing undercuts, it is possible to ensure uniform curing and prevent stress concentration that can result in dimensional control errors or deformations.

High Durability

Silicone rubber can be exposed to extreme temperatures and still maintain its mechanical properties. This feature makes it an ideal choice for applications that require the material to withstand high temperatures, such as aerospace and automotive components.

Silicone can also withstand exposure to UV rays and other environmental factors that are detrimental to many other materials. Unlike organic rubbers, which can be negatively impacted by ozone, silicone is unaffected.

Liquid silicone injection molding (LSR) produces highly detailed molds that facilitate the production of complex elastomeric parts. This process is a cost-effective option for fabricating small, complex silicone components for products that require high quality.

The LSR process can be performed in-house with specialized machinery. This reduces the amount of handling and prevents contamination of the raw materials. This closed-loop system offers superior cleanliness and is a great solution for medical applications. This can include the addition of barium sulfate to make the finished silicone radio-opaque, which can be used for wound drains and catheters.

Good Electrical Conductivity

Liquid silicone rubber possesses better electrical properties than other polymers in many applications. It has a high dielectric strength, excellent arc resistance and lower surface currents. It also resists the formation of cracks and voids during use, providing excellent reliability over a long period.

Conductive silicone rubbers are formulated with carbon and other materials to achieve specific electrical conductivity. The EC series of conductive silicone offers these special qualities along with the typical benefits of standard silicone rubbers. This product is often used as electromagnetic shielding or antistatic rubber.

Conductive silicones are able to withstand high temperatures without degrading or disintegrating. They have good heat stability and abrasion resistance, and they provide excellent environmental sealing and electrical insulation. These properties are especially important when working in environments with moderate to high pollution levels or where dry band arcing is a problem. They are also a great choice for nuclear applications due to their radiation resistance.

Resistance to Corona Discharge

Unlike normal organic rubbers, silicone parts are resistant to Corona Discharge. It can also withstand high temperatures for extended periods of time without brittleness or melting. Additionally, it is an effective insulator. The silicon-oxygen atomic bonds in the material prevent the flow of heat or electricity. This makes it an ideal choice for applications that require a protective barrier against high-voltage sparks and electric fields.

Corona aging turns the hydrophobic surface of silicone rubber into a more hydrophilic one. The deterioration of the surface can accelerate the water diffusion process, leading to microcracks on the silicone rubber. The results of the FTIR and SEM measurements indicate that the hydrophobic groups on the sample surface are degraded during the corona aging process.

The EIS results showed that the sample resistance during immersion in NaCl solution first decreased and then remained constant. The sample resistance was determined by the value of sample porosity. The concentration of free volume holes and their sizes varied with the crosslinking level. The optimum crosslinking level for composite insulator production is 1.5 wt. %.