HCR quality or high temperature vulcanized silicone rubber is used in the compression moulding press. Special silicone rubber materials are chosen based on their intended use, weather they need to be fire, oil or heat resistant. Food and medical qualities have FDA and BFR approvals.
HCR silicone has been widely used to replace petrochemical products in all industries including aerospace, munitions industry, automobile, fine chemicals, construction, electric and electronics, food processing, mechanical engineering, medical and pharmaceutical, cosmetics, home appliances, paper film, solar batteries, and semi conductor. Recently, the scope of silicone application has been expanding at a greater speed.
Characteristics of HCR:
Durable: Silicone rubber is a material of choice in industry when retention of initial shape and mechanical strength are desired under heavy thermal stress or sub-zero temperatures. Organic rubber has a carbon-to-carbon backbone which can leave it susceptible to ozone, UV, heat and other ageing factors that silicone rubber can withstand well. This makes silicone rubber one of the elastomers of choice in many extreme environments.
Chemical resistance: HCRsilicone is highly inert and does not react with most chemicals. Due to its inertness, it is used in many medical applications including medical implants. It is biocompatible, hypoallergenic and non-allergenic, which makes it suitable for baby care products, and food contact in general.
Temperature resistance: HCR silicone offers good resistance to extreme temperatures, being able to operate normally from −100 to 300 °C.
Mechanical properties: properties such as elongation, creep, cyclic flexing, tear strength, compression set, dielectric strength (at high voltage), thermal conductivity, fire resistance and in some cases tensile strength can be—at extreme temperatures—far superior to organic rubbers in general, although a few of these properties are still lower than for some specialty materials.
Electrical properties: HCR silicone has excellent insulating properties.