Superior Material for Greater Protection

Today's automotive fuels prove no match for Dayco Products Inc.'s Series 7253 curb pump hose made with Hypalon® chlorosulfonated polyethylene. The Dayton, Ohio, USA-based company's curb pump transfer gasoline and other petroleum-based automotive fuels from the service station pump to a vehicle's gasoline tank.

Because oxygenated and ozone-safe blended gasoline can deteriorate industrial fuel hoses, Dayco was looking for a durable, flexible material to guard against degradation due to vapour deterioration as well as ozone, weather and UV degradation. The company chose Hypalon® to protect people and the environment from toxic fuel spills that can occur with hoses made of inferior materials.

"It's very difficult to find material suitable for this application," said Steve Stuery, lead hose development engineer at Dayco. "Right now you can't beat the properties Hypalon® offers for this hose."

Resisting Environmental Factors

The saturated polymer backbone in Hypalon® is formulated to be ozone and weather resistant, and it will not crack prematurely when strained and exposed to harmful ozone particles. According to Steury, compounded Hypalon® also demonstrates the required flexibility and durability.

"Flexibility is critical for this application," he said. "That's why we look to a flexible synthetic elastomer like Hypalon®, which shows a high ‘flex-durability' in strength tests for the curb hose. Without the use of a suitable elastomer such as Hypalon®," Steury added, "the hose will exhibit "flex fatigue failure," resulting in separation of internal hose walls, splits in the cover and ultimately hose failure."

Dayco curb pump hoses are exposed to ozone, UV radiation, heat and harmful fuel vapors or liquids that can affect the integrity of the hose cover. These vapors and liquid fuels can erode the plasticizers that make the hose casing flexible, but Hypalon® has shown strong resistance to the degradation caused by these chemicals.

"Weatherability, one of the strongest properties of Hypalon®, was a deciding factor in Dayco's search for an elastomer suitable for the curb pump hose application," Steury said. Heat-resistant to 100°C (212°F) and useable at -40°C when properly formulated, Hypalon® performs well under extreme temperature conditions.

Color-coded Fuel Hoses

Dayco manufactures the curb pump hoses in standard black and is developing red, green, blue and yellow models. Such colors can be used to match fuel company trademarks and to indicate different fuel grades at service station pumps. For instance: green for diesel fuel, blue for unleaded, etc.

"Hypalon® demonstrates other key properties that make it the polymer of choice for a broad range of industrial applications," Steury said. When exposed to UV light, Hypalon® is color-stable and shows very little fading. It also has good abrasion resistance and mechanical toughness, which are necessary properties for industrial applications. Additionally, Hypalon® can be formulated easily for flame resistance.