MATERIALS | THERMOPLASTIC ELASTOMERS
Hardness Sh A
Tensile strength N/mm2 Elongation of break % Tear resistance N/mm
Dokument:
Compression set 70˚C/22 h Compression set 100˚C/22 h Compression set 120˚C/22 h Adhesion N/mm
TEH (PA) 73
6.3
300 18 31 35 38
2.7
TEH (PP) 67
6.5
330 19 40 37 47
6.0
Basic property data for two Kraiburg TEH compounds, one developed for adhesion to polypropylene (TEH (PP)) and the other for adhesion to polyamide (TEH (PA)). Both show very low compression set
Volume change in % IRM901 @ 120°C
10,0 15,0 20,0
-20,0 -15,0 -10,0 -5,0 0,0 5,0
0 okument: TEH (PA) 1 Weeks TEH (PP) 2 NBR
Swelling behaviour of Kraiburg TEH (PA) and TEH (PP) in ASTM reference oil IRM 901 at 120 C compared to that of a commercially available NBR-based rubber. The rubber compound shows a significant decrease in volume, which may present a problem for sealing applications. Both TEHs show lower volume change
Elongation at break change in % IRM901 @ 120°C
100,0 120,0
20,0 40,0 60,0 80,0
0,0 0 TEH (PA) 1 Weeks TEH (PP) 2 NBR
Elongation-at-break behaviour in IRM901 at 120°C. Both Kraiburg TEH materials embrittle much less than the rubber
18 INJECTION WORLD | May 2019 3 3
He also says that Kraiburg TPE has succeeded in implementing a technology platform that allows a large number of thermoplastic elastomers to be tested within a short period of time. “Whereas the initial developments took months to complete, conclusions about the suitability of a new raw-ma- terial combination can now be reached within a few test cycles and only few weeks of material testing,” he says. Kraiburg TPE has tested numerous thermoplas- tics such as PP, PE, EVA, PA, PBT and modified thermoplastics, as well as thermoplastic elastomers such as TPE, TPC, TPA and TPU as a thermoplastic phase. The elastomers that were used include NBR, H-NBR, EVM, AEM, ACM, SBR, IIR, BR, NR, EPDM and VMQ. Regular TPEs continue to improve as well, many
of them intended for over-moulding. Albis Plastic, for example, has revised and improved its Easyflow Alfater XL TPVs materials. The new Alfater XL 3EF0010 Easyflow series, in hardnesses of 50 Shore A to 40 Shore D, is a deep-black material with very good flowability. “This property makes it well-suit- ed for thin-walled components, tools with long flow paths, or complex geometries,” the company says. The new compounds have very good weather
resistance, surviving up to three annual cycles of the Florida and Kalahari tests (PV 3930 and PV 3929). They also adhere very well to filled, rein- forced, and un-reinforced PP. At SPE’s Automotive TPO Conference in Detroit last October, Trinseo introduced no fewer than four new series of TPEs. They include 16 new over-moulding grades specifically developed for automotive applications, offering improved adhesion to Trinseo’s Magnum ABS and Pulse PC/ ABS product range. Trinseo says that since it acquired Italian TPE compounder API in 2017, it has gained unique expertise in both the formulation technology and compounding processes of TPE materials. “The introduction of these new TPEs marks a milestone in the integration process as Trinseo works to further expand the synergies between its rigid- and soft-touch product portfolios,” it says. All TPE grades are produced at Trinseo’s manufacturing site in Mussolente, Italy. The plant also contains a Specialised Overmoulding Centre (SOC), where the company can measure the adhesion between substrates in accordance with VDI 2019 standards. Hexpol TPE points to the increasing need to
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provide materials with reduced emissions. It offers Dryflex Interior for such applications. On average, they offer a 75% emission reduction compared to
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