EPDM elastomers can be food grade materials if they follow the compositional guidelines set forth by the U.S. Food and Drug Administration. However, as the superior weather resistant rubber, EPDM sheets are better used outdoors or in industrial settings rather than for food handling applications. The chemical composition of EPDM allows it to have excellent resistance against degradation caused by UV rays, ozone, and oxidation. For food service applications, silicone is the best option due to its higher temperature resistance range and resistance to oil. EPDM liners are an exception as they are often used to line outdoor potable water tanks due to its resistance to damaging environmental factors. Although EPDM elastomers can be used as food grade rubber, its composition makes it better suited for outdoor or industrial applications.

Is EPDM Food Grade Rubber?

EPDM is generally an outdoor rubber material, but food grade EPDM rubber is available in the market. It is important to understand that EPDM elastomers are best used as outdoor rubber materials rather than food grade rubber. The most commonly used food grade rubber is silicone due to its high tolerance to extreme heat. According to the FDA (Food and Drug Administration), “Rubber articles intended for repeated use may be safely used in producing, manufacturing, packing, processing, preparing, treating, packaging, transporting, or holding food, subject to the provisions of this section [FDA 21 CFR 177.2600]” (accessdata.fda.gov). Food grade EPDM elastomers can be used in the making of FDA approved seals and store products due to its high resistance to extreme heat and low temperatures. With a wide operating temperature range of -40 to 212 degrees Fahrenheit, EPDM elastomers are ideal for food storage seals, such as refrigerator and freezer seals or food warmers. For instance, “As a durable elastomer, EPDM is conformable, impermeable, and a good insulator…It is used to create…seals on doors for refrigerators and freezers (where it can also act as an insulator)” (Wikipedia.org). Despite these properties of EPDM elastomers, it does not match the temperature range FDA approved silicone can withstand. As a case in point, “Silicone rubbers have excellent low temperature flexibility combined with outstanding high temperature resistance. Their service temperatures range from −70 °C to 250 °C [-94 to 482 degrees Fahrenheit]” (sciencedirect.com). Both elastomers have high tensile strengths and low compression sets, preventing them from tearing and allowing them to return to its original form after being under heavy pressure or tight seals. Furthermore, both white and black EPDM materials can be FDA approved, but most food grade rubbers are white due to aesthetic purposes. Food grade black EPDM, or any other food grade elastomer, is not popular because of its dark, industrial look. Black is a very bold color that is often associated with industrial use whereas white or gray are softer, making them the preferred colors to work with in applications for human consumption or for medical use. Although EPDM elastomers can be food grade materials, silicone is able to withstand a wider range of temperatures making it the best food grade rubber option available.

Is EPDM FDA Approved?

EPDM is generally not FDA approved; however, it can be FDA approved if it is in accordance with the FDA’s Code of Federal Regulations Title 21 177.2600. Food grade elastomers must follow strict compositional guidelines set in place by the FDA to lower the level of toxic chemicals used in their production. In reference to the FDA’s Title 21 177.2600, substances used in food handling must be deemed safe for use in food storage, have prior sanction or approval, and follow the chemical content guidelines stated in the code. EPDM elastomers are created through the crosslinking of ethylene, propylene, and three dienes. To clarify, “The diene(s) currently used in the manufacture of EPDM rubbers are dicyclopentadiene, ethylidene norbornene, and vinyl norbornene” (sciencedirect.com). Other times, ethylidene norbornene is replaced with 1, 4 hexadiene (polymerdatabase.com). For ethylene-propylene copolymer elastomers, the type made of ethylidene norbornene “may contain not more than 5 weight-percent of total polymer units derived from 5-methylene-2-norbornene and/or 5-ethylidine-2-norbornene” whereas the type made 1, 4 hexadiene should contain “no more than 8 weight-percent of total polymer units derived from 1, 4 hexadiene” (accessdata.fda.gov). Following these guidelines are extremely important as these chemicals can cause serious health ailments. For instance, ethylidene norbornene can affect respiratory health as well as cause irritation in eyes, nose, and throat” (nj.gov). Due to toxicity levels of certain chemicals used in the production of EPDM elastomers, unless it follows Title 21 177.2600, it is not FDA approved.

Is EPDM Safe for Drinking Water?

EPDM is safe for drinking water and is a popular elastomer used in applications involving human consumption once it is FDA approved. EPDM liners are often used in potable water tanks due to their impermeability and resistance to outdoor damaging factors. There are specific guidelines put forth by the U.S Environmental Protection Agency (EPA) to prevent toxic substances from leaching into the drinking water. The EPA has “established protective drinking water standards for more than 900 contaminants including drinking water regulations issued since the 1996 amendments to the Safe Drinking Water Act that strengthen public health protection” (epa.gov). Contaminants not only come from chemical solvents, but they can also leach out of toxic materials as well. Synthetic rubbers, such as EPDM elastomers, are generally the variations of rubber that are used to line potable water tanks and other means of storing or transporting potable water. In fact, “EPDM 1.0mm rubber membrane are used for potable water applications” (environmental-expert.com). EPDM liners are ideal for applications involving drinking water due to its superior resistance to water. For instance, “Ethylene propylene diene rubber (EPDM), with its superior hydrolytic stability and resistance to chloramines, is becoming more widely used in these applications” (waterworld.com). However, silicone is known for its excellent compatibility with food and drinks. Case in point, “Many experts and authorities consider silicones to be nontoxic and safe for contact with food and drink. For example, Health Canada states: "There are no known health hazards associated with use of silicone cookware. Silicone rubber does not react with food or beverages or produce any hazardous fumes’” (mindbodygreen.com). Although EPDM liners are durable, impermeable, and weather resistant rubber materials, silicone is the best and most commonly used food grade elastomer for food and drinking water.

How is EPDM Made?

EPDM is made through the cross-linking of ethylene, propylene, and diene monomers through the process of vulcanization. These chemical compounds give EPDM elastomers the ability to resist the damaging effects of abrasive environmental factors such as UV rays, ozone, moisture, and oxidation. The level of environmental resistance, in particular, depends on the ethylene or propylene content in the formulation of this weather resistant rubber material. A case in point, “The double bonds in ethylene and propylene molecules (and one of the double bonds in the diene molecules) are opened so that one single bond can be used to link to a carbon atom of another molecule…EPDM , with the double bonds located in the side groups, is much less susceptible to degradation by weathering and sunlight; although the double bonds can be broken by ozonolysis, thermal deterioration, or oxidation, such processes will not break the main chains” (Britannica.com). In addition, due to these environmental resistance properties, EPDM elastomers are known for being a crack-less rubber that is able to withstand damaging outdoor factors as well as impacts and abrasions.

Is EPDM Heat Resistant?

EPDM is a highly heat resistant material with the ability to withstand both extreme high and low temperatures. Due to its high resistance to abrasive temperatures, EPDM sheets are capable of being used in high temperature applications without failing or becoming damaged. Being able to stand up well against temperatures as high as 212 degrees Fahrenheit, EPDM sheets are the ideal heat resistant materials for thermal and electrical insulation. Food grade FDA approved EPDM sheets can be used for food related applications; however, silicone is able to withstand higher temperatures making it the better food grade rubber over EPDM elastomers. EPDM is a diene elastomer, meaning it is a weather resistant rubber that stands up well against heat, ozone, and UV rays. For instance, “Diene elastomers that have electron-donating groups attached to the diene are usually the least stable rubbers (NR, IR), i.e. they have poor heat, ozone and UV resistance, whereas elastomers with a low number of double bonds (HNBR, IIR, EPDM) have good or even excellent heat resistance” (polymerdatabase.com). This is made possible due to EPDM’s stable, saturated polymer backbone. As a case in point, EPDM elastomers are “synthetic rubber(s) having outstanding heat…resistance due to their stable, saturated backbone structure” (springer.com). Although EPDM sheets are highly resistant to damage caused by heat, but it is less heat resistant than silicone rubber making it less suitable for heated applications involving food compared to food grade silicone.

Is EPDM Rubber Oil Resistant?

While EPDM is highly resistant to the damaging effects of most industrial chemicals, it is not an oil resistant material. EPDM elastomers have excellent resistance to chemicals, allowing EPDM products to be used in chemically related applications; however, “like other hydrocarbon elastomers, the ethylene-propylene copolymers are swollen and weakened by hydrocarbon oils” (Britannica.com). Sometimes, EPDM elastomers can be used in the presence of mineral oils; however, it can only be used in static applications because it will be subjected to 10 to 20 percent volume swell where applicable. Mineral oil is “a clear, odorless liquid and a common ingredient in a variety of cosmetics and personal care products. Mineral oil is made from highly refined, purified and processed petroleum” (chemicalsafetyfacts.org). This non-toxic oil can also be used in food along with cosmetics. However, when looking for an oil resistant food grade rubber, silicone would be your best option due to its high heat and oil resistance along with its non-reactive with food and beverages and will not emit any toxic fumes when heated while cooking. EPDM elastomers are resistant to mineral oils, but it will not be resistant to industrial oils as well as other cooking oils making silicone best suited for food service applications.

Is EPDM a Silicone?

EPDM is not a silicone and is an entirely separate synthetic elastomer. Although both synthetic elastomers are used in similar applications, silicone is an inorganic material that is most often used in food service applications. EPDM elastomers are comprised of ethylene, propylene, and diene monomers while silicone is “an inorganic polymer that comprises of silicone, with carbon, hydrogen, and oxygen” (medium.com). EPDM and silicone are highly durable synthetic rubber materials; however, they have different properties that makes each better suited for different applications. Both are heat resistant materials that can also stand up well against damaging environmental factors. Additionally, they both retain high tensile strengths allowing for excellent tear resistance while being stretched to extreme lengths. However, silicone and EPDM elastomers are commonly used for different applications. Although they both have a high tolerance to heat, silicone rubber is able to withstand highs of up to +500 degrees Fahrenheit whereas EPDM elastomers can only withstand temperatures as high as 212 degrees Fahrenheit. This allows silicone to be a better food grade rubber than EPDM along with the fact that silicone is highly non-reactive to food and is ideal for use in applications involving materials for human consumption. Silicone rubber is best known for being a food safe rubber and is often used in food storage and cooking applications while EPDM elastomers are better used in outdoor or industrial settings.

Does EPDM Contain Silicone?

EPDM does not contain silicone, but it does contain ethylene, propylene, and diene monomers. Although both elastomers are considered synthetic, silicone is an inorganic material derived from sand. EPDM elastomers, on the other hand, is made up of chemical compounds that allow it to be the superior weather resistant rubber that will not degrade under harsh UV rays or ozone. The chemical compounds used in the production of EPDM sheets are very specific due to their effect on the rubber’s physical and chemical properties. Specifically, the level of ethylene content used in the production of EPDM dictates the physical properties of the elastomer. For instance, “it has been reported that the ethylene content influences the properties of the EPDM polymers [12], and that a higher ethylene content gives more green strength (high elongation in the uncured state), poorer low temperature properties, imparts a more crystalline nature to the EPDM and increases its glass transition temperature” (core.ac.uk). Moreover, silicone is a food safe and hypoallergenic material that is better suited for applications involved with human consumption.

As the superior weather resistant rubber, EPDM elastomers are ideal for outdoor or industrial use; however, certain variations that have been approved by the U.S. Food and Drug Administration can be used in food service applications. An example of this can be seen in EPDM liners that are often used to line potable water tanks due to the elastomer’s high impermeability and weather resistance. Silicone rubber, on the other hand, is ideal for food related applications as it is highly non-reactive to food, beverages, and cooking oils, making it the best food grade rubber available, even over EPDM elastomers. EPDM sheets are resilient synthetic rubber materials that are ideal for outdoor usage rather than food related applications.