Hytrel® HTR8808 is a thermoplastic polyester elastomer (TPEE) grade used in high temperature applications, exhibiting outstanding balance of heat resistance and stiffness, high flexibility and pressure resistance. Its key feature is its cyclical flexibility in all directions while being highly durable, making it very useful in applications within the automotive industry.
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Thermoplastic elastomers (TPEs), also known as thermoplastic rubbers, are a group of polymers that integrate the characteristics and features of both elastomers and plastics, resulting in enhanced material properties. Just like rubber, TPEs exhibit excellent flexibility with a very low elastic modulus and good recyclability and processability without requiring any stabilisers or reinforcing agents. They are made of two phases, one soft and amorphous and one hard and crystalline. This biphasic structure brings about both high strength and tear resistance from one side, and high hardness and flexibility from the other. Some types of thermoplastic elastomers include styrenic block copolymers (S-TPEs), olefinic blends (TPOs), thermoplastic vulcanizates (TPVs), polyurethanes (TPUs), copolyesters (COPEs), and polyamides (PEBAs).
The Hytrel® family is a group of high-performance engineering thermoplastic elastomers that show both thermoplastic and elastomeric properties, including outstanding toughness, high impact and creep strength, resilience and fatigue strength.
Manufactured by DuPont™, Hytrel® is identified by ISO 1043 as a thermoplastic polyester elastomer (TPEE). As a block copolymer, its excellent properties arise from its biphasic composition of hard and soft segments, rendering it suitable for air ducts in turbo gasoline engines.
Hytrel® HTR8808, a finalist in the 2019 R&D 100 awards [1], is a high-performance TPEE material which can be extruded for wire and cable, tubing, or optical fibre extrusion, down to extremely thin wall thickness (0.2 mm). Its combination of high-temperature performance, excellent chemical resistance, high processability, and outstanding flexibility allows it to be a material of interest in high-performance applications.
Some of its more significant material properties include a very low elastic modulus, good heat resistance, and good level of hardness. Here’s a list of its key features.
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Key features and properties of Hytrel® HTR8808 |
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High chemical resistance |
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Good hardness |
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Low elastic modulus, cyclical flexibility |
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Excellent toughness |
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Good fatigue strength |
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High creep and impact resistance |
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Pressure resistance |
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Good heat resistance |
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High thermoplastic processability |
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Good recyclability |
Hytrel® HTR8808 is suitable for processing by blow moulding, which is a manufacturing process that produces plastic parts by forming a molten tube of thermoplastic material – also called a preform – putting it inside a mould cavity, and expanding the tube using blown compressed air until it takes the shape of the mould, where it then cools down before being detached from it. This method is convenient for any hollow thermoplastic component. Its three main types are extrusion blow moulding (EBM), injection blow moulding (IBM), and injection stretch blow moulding (ISBM) [2]. What makes it advantageous in plastic part production is its lower cost compared to injection moulding, low machinery costs, and its one-piece construction. Hytrel® HTR8808 is recyclable as thermoplastics can be melted, cooled, solidified, and then melted again without burning.
Hytrel® HTR8808, with its flexibility in different directions and its high durability, can be used within the automotive industry to manufacture pressurised hot side air ducts for turbo gasoline engines. As a fully integrated flexible duct, a Hytrel® HTR8808-based air duct can take the place of traditional rigid air ducts, which are usually made of metals or polyamide 6 glass filled materials. It can also replace injection welded ducts, rubber turbo hoses, and textile reinforcements [3].
[1] “DuPont Wins Two Prestigious R&D 100 Awards for Advancements in Science & Innovation”, DuPont, [Online] Available from: https://www.dupont.com/news/dupont-wins-two-awards-for-science-innovation.html, 2019.
[2] “What is blow molding?”, [Online] Available from: https://www.milacron.com/mblog/2018/02/28/what-is-blow-molding/, 2018.
[3] “DuPont Performance Materials launches new product lines at K 2016”, [Online] Available from: https://www.plastech.biz/en/news/DuPont-Performance-Materials-launches-new-product-lines-at-K-10884, 2016.