Silicones are among the most versatile and unique elastomers in the market today. Typically, silicones are popular due to their broad temperature latitude. For instance, certain silicones will resist temperatures as high as 280 ̊C. On the other hand, silicones when exposed to extreme cold will retain their suppleness and flexibility to -70 ̊C. Additionally, silicone can be formulated to have very low compression set properties, which is highly desirable for environmental and static seals. As an electrical insulation material, silicone is superior. And, of special interest, silicone can even be made electrically conductive via formulation. Its resistance to oxidation, UV exposure, and ozone makes it a leading candidate for many outdoor applications. Further, due to its physiological inertness, silicone is the choice for handling fluids intended for human consumption. The elastomer is virtually odorless, tasteless and non-toxic when properly selected. Silicone in its raw state is semi-translucent and can be pigmented in a wide array of colors.
Fluorosilicone elastomers are basically specially prepared silicones in which fluorine substitutions are made on the polymer chain. This substitution provides enhanced fluid resistance particularly to fuels and oils. It has the same superior low temperature flexibility as silicone. A limitation is that high temperature service exposure should be limited to 175 ̊C. Typically, fluorosilicone is used in O-rings, although due to it’s unique fluid resistance, it is even found in some dynamic applications. Further, in military environments, it is preferred for it’s fluid resistance and extended high/low temperature profile. Fluorosilicone can also be compounded for very low compression set and oxidative stability.
Fluorocarbon elastomers are essentially highly fluorinated hydrocarbon polymers. Typical trade names of fluorocarbons are Viton®(Dow-Dupont) and Fluorel® (3M). The high degree of fluorination results in an exceptionally stable elastomer. These elastomers are highly resistant to chemical attack, flame, oxidation, sunlight and ozone. The automotive industry strongly favors fluorocarbon for areas in contact with fuels and oils like, O-rings, seals, diaphragms and fuel hose. These products are heat stable up to 200 ̊C under continuous service applications. On the other extreme, fluorocarbons are useful at temperatures as low as -20 ̊C; with proper formulation, one can extend the service temperature to -40 ̊C, but only in static sealing applications. They can be designed for low compression set requirements with a tailored compound. Another nice feature of fluorocarbon elastomers is their imperviousness to gases, approaching that of the butyl family.
EPDM elastomers are terpolymers of ethylene, propylene and a non-conjugated diene polymers. Generally a very cost-effective elastomer, EPDM exhibits exceptional electrical insulative properties making it a top candidate in wire and cable jacketing. As a highly stable polymer, EPDM resists aging from weather, ozone, water and certain chemical exposures. In fact, its resistance to water and engine coolants make it the choice for automotive coolant hose. Its low cost allows its use in such consumer goods as garden hose. Its superior UV resistance has landed it in commercial rubber roofing where sunlight exposure would be punishing to most elastomers. This adaptable material is available in tubing, profile extrusions and moldings in a variety of hardnesses and properties. EPDM is usually black in color, although we offer it in other colors as well. For your door, window seal or gasket application, consider EPDM elastomers.
Nitrile elastomers are co-polymers of acrylonitrile and butadiene. The elastomer is designed with varying levels of acrylonitrile (ACN). The higher the content of ACN in the polymer design, the better the resistance to gasoline and aromatic oils. The lower the content of ACN, the lower the resistance to these fluids becomes. However, the lower the ACN elastomers exhibit improved low temperature flexibility and resistance. Generally, nitriles are the most extensively used polymers for environments where fuel and oil exposure are the norm, such as seals, gaskets, diaphragmatic and oil field products. Select a general purpose nitrile, or review custom applications with our engineers for enhanced properties such as compression set and chemical resistance.
Isoprene is a man-made, synthetic version of natural rubber. The principal backbone of isoprene is cis-1,4 polyisoprene. Isoprene, like natural rubber, exhibits very high tensile strength, good hysteresis and good tack. A major advantage of isoprene rubber is that it does not contain the non-rubbery contaminants that natural rubber brings along with it. It is also a much more consistent repeatable polymer from lot to lot. Uses of isoprene are widespread, from baby bottle nipples to tires; pharmaceutical supplies to motor mounts; rubber bands to shoes.
Chloroprene (or by its duPont trade name Neoprene®) is a cost effective material with a broad physical property profile which explains its use in a wide scope of applications. It has relatively good resistance to ozone, cracking, heat aging and chemical attack. Specifically, Chloroprene is resistant to silicate esters, silicone oils, aliphatic hydrocarbons, and refrigerants such as Freon®. It can be formulated to exhibit low flammability as well as the ability to self- extinguish. It is not the best selection for electrical insulative properties, or for low temperature applications. Chloroprene’s physical toughness has contributed to its broad use in wire and cable sheathing, automotive hose, garden hose, and belting. Consumer applications include scuba wet suits, shoe soles and coated fabrics.
Natural rubber is derived from the Hevea Brasiliensis tree which was indigenous to the Amazon Valley. The Hevea tree is tapped and the latex sap collected for further processing. In order to meet the demands of the Western industrial boom, the Hevea was propagated and sent to Asian countries for market expansion. Today, major producers are large estates in Malaysia, Indonesia and Thailand. Its major features are high tensile strength and high tear, abrasion and fatigue resistance. High resiliency allows low heat buildup in the rubber, making it an ideal candidate for tires and other dynamic applications. It is a choice candidate for vibration mounts, bridge bearings and pharmaceutical closures. Other uses include latex products: rubber gloves, carpet backing and adhesives. Principal drawbacks are poor ozone and weather resistance and two year service life in outdoor environments. Its medical use is limited due to the presence of proteins, amino acids and other non-rubber components thought to contribute to allergic reactions in certain individuals.