Why is High Consistency Rubber ideal for molding applications?

Manufacturers in various industries, including automotive, healthcare, general industrial, infant care, consumer goods and electronics require easy-to-mold (and demold) low or high-viscosity rubber silicones to produce parts efficiently and cost-effectively.

Heat Cured Rubber, or High Consistency Rubber (HCR) is a silicone elastomer formed of straight chains with very high molecular weight. This system is cured with an organic peroxide crosslinker or a platinum catalyst. The silicone backbone is composed of repeating Si-O chains which are extremely flexible in nature giving this chemical structure unique properties such as a broad operating temperature range, weatherability, being hydrophobic, bio-inertness, electrical insulation, and an overall long-life span.

High Consistency Rubber (HCR) is the material of choice in manufacturing rubber parts through transfer molding process or compression molding. HCRs have outstanding properties and are far superior to conventional organic elastomers including good thermal stability, excellent mechanical strength, and fire resistant with low smoke emissions and non-corrosive and non-toxic combustion gasses.

Discover our latest video "What is HCR Silicone?"

High Consistency Rubber (HCR)


Transfer molding or compression molding are ideal processes for high consistency rubbers (HCRs), especially for manufacturing large parts.

  • Transfer molding process is a closed mold system that incorporates a container above the mold where the rubber sits and gets pushed into the mold using a piston-powered gate system. This process transfers the silicone material into the mold and heats it under pressure to produce the cured part. Silicone transfer molding process is ideal for manufacturing high precision silicone molded parts as well as overmolding with other materials and allowing for molding complex geometries. The combination of HCR silicone rubber and the transfer molding process leads to high quality manufactured parts that offer design flexibility and shorter production cycles than other types of molding.
  • Compression molding uses high pressure to squeeze a pre-formed piece of rubber into a mold between two or more plates, depending on the part or product configuration. This process is generally done by hand in the open mold where the mold is closed, the silicone rubber cures, then the part is demolded. This method of molding silicone rubber is used for manufacturing simple rubber parts that can be easy to manufacture prototypes in a wide range of part sizes.

Elkem Silicones works with you to define which compounds are the most cost-effective and best suited to your processing conditions, to achieve the performance levels you require. Our technical team has expertise on both materials and can advise you in your choice and all along your development.