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Trends, guidance on material selection, and advances in new mate- rials were addressed at the recent Silicone Elastomers and Thermoplastic Elastomers Summit U.S. 2017. Organized by the U.K.'s Smithers Rapra, it was the first time in five years for this dual conference, held in Philadelphia in late June. New LSRs were presented by Dow Corning and Momentive Performance Materials; while new TPEs were highlighted by PolyOne, DSM Engineering Plastics, and Hexpol TPE. Consultants Bob Eller of Robert Eller Associates, Akron, Ohio (robertellerassoc.com), and Patrick Ellis of Smithers Rapra (U.S. office in Akron; smithersrapra. com), both addressed the global TPE industry and future opportunities. Eller identi- fied key growth sectors for TPEs: medical/pharmaceu- tical, packaging, and automo- tive, including autonomous/ semi-autonomous vehicles. Regarding the latter, Eller says there are opportunities in "smart surfaces" with integrated electronics providing display, sensor, and switching func- tions; as well as improving acoustics. Innovation strategies he cited include 3D printing and use of new nano-scale additives for conductivity, foaming, or sensing functions. Ellis noted that there is a large performance gap between commodity TPEs and high- performance TPEs. Current market requirements include better long-term heat resistance (392 F) for automotive; long-term chemical resistance (fuels, oils greases, glycols) for automotive and industrial uses; and better high-temperature compression set (<20% at 212 F) for seals and gaskets. He forecasts that copolyester TPEs, because of their high-heat resistance, will grow significantly in automotive. MATERIAL-SELECTION GUIDANCE There were two presentations on how to select the right material. "Choosing the Right TPE: The Seven Essential Considerations" was presented by Brian Mulvany, sr. market manager for consumer, electrical, and global key accounts for the TPE div. of Teknor Apex, Pawtucket, R.I. (teknorapex.com). The seven guidance points are: intent/application for TPE selection; manufacturing process; cost targets; environmental conditions; regulatory concerns; surface aes- thetics and haptics; and material performance characteristics. "Choosing the Right TPE for Overmolding Applications" was presented by Jim Ingram, devel- opment engineer at A.Schulman, Fairlawn, Ohio. (aschulman.com). He discussed overmolding and adhesion principles and testing methods. He also addressed insert molding, two-shot molding and coinjection molding and each method's pros and cons. Another presentation, "Silicone vs. TPE," was presented by Lynn Momrow-Zielinsky, president and co-owner of Extreme Molding, Watervliet, N.Y. (extrememolding.com), a custom injection molder of LSR and TPE healthcare items for women and infants, and more recently a variety of PET molded products. Among the company's special- ties is hard/soft overmolding of LSR or TPE onto rigid thermoplastics. She addressed material attributes of LSR vs. TPEs, processing details, and how to choose between them for a particular application. She noted that TPEs have superior adhesion for overmolding onto most plastics, whereas LSRs are more difficult unless overmolded onto another LSR. ADVANCES IN LSR Several new LSRs were discussed by Hans Peter Wolf, manager of R&D; for silicone rubber at Dow Corning, Midland, Mich. (dowcorning.com). Among them was Silastic LC 3335 for 3D printing with filament- By Lilli Manolis Sherman, Senior Editor LSR & TPE Summit Highlights Trends And New Materials Among them: an LSR for 3D printing and low-VOC TPEs for auto interiors. One focus for LSR developments is grades that cure at low enough temperatures for overmolding onto PE and PP. Both Dow Corning and Momentive have developed low- VOC LSRs for such wearable items as sports watches, and Dow Corning also launched a low-VOC, non-postcure LSR for baby products. 16 SEPTEMBER 2017 Plastics Technology PTonline.com M AT E R I A L S Close -Up On Technolog y