Consumer products, sporting goods, automotive components, wire and cable,
industrial equipment, and biomedical devices. These, indeed, represent a diverse
range of products. But, in many instances, they have one important element in
common-thermoplastic elastomers (TPEs).
The reasoning behind TPEs' choice is not hard to understand. They are a versatile group of resins. Consider, for example, some of their innate property characteristics:
These linear segmented polymers consist of hard and soft ingredients. By varying the relative amounts of the hard and soft components, the resins can meet a wide range of flexibility and performance requirements. This choice alone lets engineers optimize the material to match design criteria when it comes to everything from color or clarity to indoor or outdoor uses.
They are environmentally friendly. Recent resin introductions have expanded this friendliness to include improved recyclability and non-toxin-containing formulations.
Advances in processing technology enable TPEs to be tailored to meet almost any design need, while improving product quality and cost.
Wrap these features in a package and it's little wonder that TPEs have become an increasingly popular entry on the design engineer's material list.
To better illustrate this adaptability, let's look at two industry areas-automotive and medical-where TPEs are making serious inroads as replacements for metals or to complement other plastic materials.
Automotive electronics provide a perfect example of how TPEs can adapt to the changing design needs. The explosion of electronic features in today's automobiles has caused a corresponding increase in the size of electric wiring harnesses. Packaging constraints due to this trend are driving a downsizing of electrical systems. Engineers have accomplished this in two ways: reducing conductor wires, which results in higher operating temperatures, or reducing the thickness of the insulating materials, which requires the need for greater insulating efficiency.
DSM Engineering Plastics has introduced a series of TPEs, Arnitel(R) V, that addresses the needs of both problems. Arnitel UM551-V, a non-halogenated, flame-retardant grade, answers the primary wire insulation obstacle, while Arnitel UM552 fulfills the need for components that require high-temperature resistance, but not flame retardancy.
DSM, the Netherlands-based parent of DSM Engineering, acquired the Arnitel product line from Akzo in 1991. In Europe, Arnitel U has replaced PVC and cross-linked polyethylene based on its environmental, process, recycling, and performance advantages. Relative to other polyester elastomers and typical wiring insulation materials, says Steve Hartig, DSM Engineering Plastics' automotive industry manager, Arnitel can offer:
Continuous-use temperature capability for natural materials up to 338 degrees F (170 degrees C), and for non-halogenated, flame-retardant grades up to 302 degrees F (150 degrees C).
Twice the abrasion resistance.
Excellent UV stability and color fastness.
"We have the expertise of our TPE division here in the U.S., and the experience of thermoplastic manufacturing in Europe," Hartig adds. "This will enable Arnitel UM551-V to find an important niche in automotive under-hood cabling systems."
And when it comes to heat- and oil-resistant materials, particularly for such automotive applications as O-rings, seals, and gaskets, don't overlook a new class of specialty elastomers from DuPont. The Advanta 332 degrees and 365 degrees materials consist of compatible alloys of proprietary