Compression Molding CompoundsCompression molding compounds are available to support a broad range of applications for molded rubber gaskets, cushioning pads and custom rubber components. Stockwell Elastomerics specializes in compression molding small to mid-range production requirements on-site at its Philadelphia facility to service fast-turn requirements, along with specialty applications in the technology sectors. Compression molding materials are mixed off-site to maintain the cleanliness of the molding facility and stored cold to extend shelf life of the catalyzed compound.
Silicone rubber compounds are inventoried from 25 to 80 durometer Shore A. Stockwell Elastomerics' compounds follow the ASTM D2000 classification standard. These are gum based compounds, in contrast to the 2-part liquid silicone rubber compounds that support our liquid injection molding processes. Most of our compression molding silicone compounds are methyl vinyl based, which can be formulated for high elongation, flex, tensile and tear properties for mechanically demanding applications and withstand temperatures from -100°F to 500°F. Phenyl based silicones are intended for very low temperatures, down to -130°F that can be required in rubber gaskets for laboratory instrumentation and aerospace applications. Gum based silicones for compression molding can be formulated to meet a number of industrial and military specifications such as ZZ-R-765 and AA-59988.
Specialty Silicone Compounds / Compression Molding Materials
Electrically conductive compounds such as electrically conductive nickel-graphite filled silicone, silver filled silicone and carbon filled conductive silicone are used in compression molding for EMI Shielding gaskets and components to promote ESD protection. The silver filled silicone is the most conductive but cost the most of the compounds mentioned above, whereas the carbon filled is the least conductive but the most cost effective. The customer service team at Stockwell Elastomerics helps customers select the compound that best suits specifications.
Thermally conductive silicone compounds are available for molded thermal interface pads used in electronics and thermally conductive gaskets used in medical sterilization and heat sealing.
Platinum cure silicone compounds, also referred to as addition cure silicones, are formulated for high strength and purity. The purity or "clean" is the primary selling point for these compounds, hence they are most frequently used in the medical and food industries. The platinum cure silicones also tend to exhibit high tear strength properties.
Fluorosilicone rubber compounds are primarily chosen because of their ability to resist fuels and chemicals as well as for the temperature range that silicones typically exhibit. Stockwell inventories the 40 and 60 durometer Shore A compounds that are certified to Mil-R-25988. Stockwell also has other fluorosilicone compounds meeting AMS and commercial compounds. These flourosilicone compounds follow the ASTM D-2000 classification standard.
Neoprene compounds are inventoried from 20 to 70 durometer Shore A. Neoprene compounds are available for Mil-R-6855, Class 2 in 40 and 60 durometer Shore A and Mil-G-1149, Type 1, Class 1. Neoprene is typically chosen for its durability, resistance to ozone, oil and some chemicals.
Semi-conductive neoprene compounds are available in 55 and 70 durometer for cushioning pads with ESD protection properties. Although neoprene is considered flame retardant, Stockwell Elastomerics has a special compound for mass transit requirements for flame propagation and smoke density.
EPDM, Nitrile (Buna-N), Natural Rubber and Viton® fluoroelastomer rubber compression molding compounds are readily available if your application is best served by one of these materials.
Special rubber sheets - Stockwell Elastomerics frequently receives requests for compression molded sheets in non-standard gauges to support rapid prototype development for aerospace equipment, instrumentation and medical equipment. Our 12" x 12" and 14" x 14" sheet molds serve these needs. Silicones and fluorosilicones can be compression molded into sheets from .030" thick through .500" thick. Neoprenes, Buna-N and EPDM compounds can be compression molded into sheets from .062" thick through .500" thick. Finished gaskets can then be waterjet or diecut from the sheets.
Contact Stockwell Elastomerics for Compression Molding CompoundsContact Us for further assistance with compression molding compounds / compresssion molded materials to support applications for compression molded rubber gaskets, cushioning pads and custom rubber components.
DuPont™ Viton® is a registered trademark of DuPont™ Performance Elastomers.
Molded FDA and Heat Seal Silicones
RMA Molding Tolerances