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Zytel polyamide resins from DuPont (Le Grand-Saconnex, Switzerland) have been selected by two automotive fluid circulation specialists for the fabrication of rigid and flexible coolant pipes. The materials advance lightweighting objectives while achieving long-term resistance to aggressive water/glycol and road salts and withstanding temperatures from -40° to 125°C.

PlasticsToday Staff

October 18, 2014

2 Min Read
DuPont polyamides lightweight auto coolant pipes

Zytel polyamide resins from DuPont (Le Grand-Saconnex, Switzerland) have been selected by two automotive fluid circulation specialists for the fabrication of rigid and flexible coolant pipes. The materials advance lightweighting objectives while achieving long-term resistance to aggressive water/glycol and road salts and withstanding temperatures from -40° to 125°C. Tristone Flowtech Group (Frankfurt, Germany) selected the Zytel PA612 long-chain polyamide (LCPA) for a flexible pipe, while Teklas Kauçuk AS (Kocaeli, Turkey) chose glass-reinforced Zytel PA66 to ensure rigidity and durability. DuPont featured the coolant pipes at its stand at Fakuma in Friedrichshafen, Germany, last week.

The flexible coolant pipe application has been nominated by the Society of Plastics Engineers (SPE) in the chassis category for the "Most Innovative Use of Plastics Award." Winners will be announced at the annual awards banquet in Detroit, MI, on Nov. 12.

Sixty percent weight reduction

Tristone Flowtech Group was looking for a material and technology for an unusually long 2- to 3-m variable flexibility coolant pipe to transport water and glycol fluid from the radiator end tank to the engine at the back, while saving weight. The challenge was not so much the length of the part, since it was extruded, but producing large pipes in diameters measuring up to 27 mm, structured in two layers with convoluted sections, that would resist 3 bar pressure, aggressive fluids, and road salt.

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DuPont provided the solution via a combination of Zytel PA612 LCPA and its patented Variable Stiffness Bellows (VSB) technology, enabling flexibility and pressure resistance in thermoplastic parts. The new pipe can withstand engine compartment temperatures of 150°C, aggressive fluid temperatures up to 120°C combined with road salt, and continuous working temperatures of 95°C. In this application, Zytel PA612 in a corrugated extrusion offers a lightweight alternative to metal, enabling up to 60% weight reduction over the former aluminum component.

"The key to developing such a large-diameter coolant pipe using thermoplastics is to balance material behavior with design, testing, and processing. Zytel PA612 LCPA and DuPont's VSB technology were critical to the technical success of the project," said Patrick Gabriel, Key Account Manager at Tristone Flowtech Group.

As for the rigid coolant pipes made from Zytel GR PA66, they can withstand temperatures up to 150°C, pressure to 2.4 bar, and mechanical stresses in hot and confined engine compartments. Added benefits include part integration and weight reduction.

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