MATERIALS | THERMOPLASTIC ELASTOMERS


Above: Cowl grille has a TPE seal


also highlights the good adhesion of Alfater XL 4PA0010 when using insert moulding technology with cold inserts. Albis is targeting hard-soft


components in sectors such as automo- tive, electronics, and the mechanical engineering industries. “In addition, the high flowability of the Alfater XL 4PA0010 series makes it available for the production of thin-walled products having complex designs and/or long flow paths,” it says. The material’s high temperature resistance also makes it suitable for use in under the hood applications such as seals, covers, and cable ducts. DuraGrip MPE (Melt-Processable Elastomer)


grades from A. Schulman can be over-moulded onto polyolefins (the 6000 series), polyamides, thermoplastic polyesters and styrenics (6100 series). The company says both series have excellent UV resistance, low temperature flexibility, and fluid resistance, as well as high scratch/mar resistance. DuraGrip is available for continuous use up to 100°C. Depending on the application, grades are available in hardnesses from 30-90 Shore A and certain grades are available in FDA compliant formulations. Applications include automotive fender flares, tool handles, kitchen utensils, and furniture. A new application for over-moulding DuraGrip


6070BK is in an automotive cowl grille seal, which is over-moulded to a grille in a filled PP. “DuraGrip 6070BK has cohesive bond strength failure of 29 pli [5 N/mm] with filled PP which is more strength than necessary for a long lasting, strong bond,” says Jessica Patz, and application development engineer


at A. Schulman. It also has high chemical resistance, low temperature properties, tear resistance, abrasion resistance, and UV and ozone resistance. Staying with automotive, Teknor Apex says a new Sarlink styrene block copolymer TPE (TPE-S), for automotive interior parts such as cable ducts and grommets, exhibits improved injection mouldability compared with other elastomers while providing competitive physical properties and meeting stringent OEM requirements. Sarlink ML-2355B has been approved by


Volkswagen for ducts that guide cables through the spaces in pillars and other structures surround- ing the passenger compartment. Teknor Apex says these ducts are complex parts with long flow paths and many undercuts, “making them a challenge to mould and de-mould. “Compared with other elastomers used for cable


ducts, new Sarlink ML-2355B exhibits reduced viscosity for improved mouldability, a wider processing window, and greater weld-line strength to facilitate air-assist de-moulding. Unlike standard TPE-S compounds, it does not exhibit stress marks caused by deformation during mould release, and it avoids the de-moulding difficulties posed by TPVs in parts with severe undercuts.” Jeffrey Dickerhoof, senior sales and marketing manager for the Thermoplastic Elastomer Division of Teknor Apex, says further that the enhanced processability of Sarlink ML-2355B provides better surface quality and fewer sink marks than standard TPE-S materials, while exhibiting lower processing temperatures, faster cavity filling, and improved mould release. Sarlink ML-2355B is a black 55 Shore A compound. OEM part requirements for the VAG cable duct include an operational temperature range of -40°C to 90°C; burning behaviour meeting the TL-1010 flammability standard for passenger compart- ments; electrical insulation meeting specification PV 1015; a water-tight seal; and passage of natural weathering tests for one year in both hot and


Properties of Teknor Apex Sarlink ML-2355B in comparison with EPDM and TPV Typical Properties Hardness Shore A Density g/cc


Tensile strength (MPa) At break


Tensile strength (MPa) at 500% elongation Elongation at break (%)


Compression set (%) 22 hrs at 70°C Compression set (%) 70 hrs at 90°C Brittleness Point (°C)


40 INJECTION WORLD | September 2017


Test Method ISO 868 (15 s) ISO 1183 ISO 37 ISO 37 ISO 37


ISO 815 ISO 815 ISO 812


EPDM 51


1.105 12.0 1.0


783 20 40


-52 (break)


High-Flow TPV 57


0.846 4.0 2.0


400 45 50


<-60 (no break)


Sarlink TPE Ml-2355b 52


1.059 5.3 1.7


678 50 70


<-60 (no break) www.injectionworld.com


PHOTO: A. SCHULMAN


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