CompositesWorld
Issue link: https://cw.epubxp.com/i/866813
SEPTEMBER 2017 74 CompositesWorld FEATURE / Advances in SMC and, reportedly, parts filled the mold/part geometry completely, including ribs and bosses. "ere definitely is a market need — and many market requests from OEMs and molders — to develop a system like this," adds ter Heide. "e industry had the capacity to develop such a material, plus epoxy is well known for its compatibility with carbon fiber for higher strength applications." A. Schulman, which reports it has produced glass/epoxy and carbon fiber/epoxy SMC since 1987, has recently introduced four grades of "next-generation, styrene-free, low-VOC" epoxy SMC reinforced with 3K- and 12K-tow chopped carbon fiber as well as continuous-fiber mat. e new materials are said to be built on technologies historically used in aerospace, military and defense markets, but specifically formulated for automotive SMC. e grades offer higher mechanicals than carbon fiber-reinforced VE SMC and have a T g that comes in between Tan Delta and storage modulus values of 125°C and 160°C respectively, which should make them compatible even with higher temperature North American E-coat lines. Customers in Europe and North America reportedly are now sampling these materials. In addition, the company also produces SMC grades with phenolic, as well as high-temperature polyimide and bismaleimide resins reinforced with carbon or glass or both for aerospace and oil and gas customers. Additionally, Magna Exteriors (Troy, MI, US) reports that since 2008-2009, the company has used in-house compounded epoxy- urethane hybrid SMC, based on Derakane VE resin from Ashland Reportedly, the system is styrene-free, low in VOCs and fully compatible with other epoxy composites on the market. Further, it has been formulated to offer excellent wetout and maximum fiber volume fraction (FVF), and it works with all common SMC reinforcements, including fiberglass. Hexion reports good quality in molded parts at up to 55 vol% reinforcement, using automotive grades of fiber. Typical molding conditions are 3 minutes at 150°C or 5 minutes at 140°C, with the lower-temperature option yielding the better surface finish. e T g of this low-viscosity system is ~100°C, so molded parts are said to be able to survive E-coat (electrophoretic painting/rust proofing) processes — at least on European if not North American lines — and can handle paint- line temperatures as well, as long as parts are shielded and well- supported during the processes. "It was quite a product design challenge to create a B-stageable system that directly replicates the maturation step typical of UP and VE systems in pure epoxy resin," notes Sigrid ter Heide, global market development manager, Transportation EPCD, Hexion BV (Rotterdam, e Netherlands). e current formulation is driven by temperature and needs 7 days of maturation at room tempera- ture or 3 days at 30°C. Recently, the new system was trialed using 45 vol%/57 wt% carbon fiber, Pyrofil 15K with 0.4% epoxy-compatible sizing from Mitsubishi Chemical Carbon Fiber and Composites Inc. (Sacramento, CA, US) on an automotive seat-frame structure with a surface area of 0.35m 2 . e initial charge area was 25% PRESENTER PRESENTED BY siemens.com/plm/fibersim DR DAVID J. HUGHES CENG, MIMM, FHEA Senior Lecturer Materials Engineering, Teesside University EVENT DESCRIPTION: is presentation will explore a series of current trends in the automotive composite sector. ese will include waste reduction techniques, fibre recycling and thermoplastic composites. We will review the use of geopolymers as performance surface materials enabling significant improvements in thermal degradation and service temperature of composite structures. e webinar will also address the current composite design skills gap and how Fibersim is being integrated into Teesside University's undergraduate degree program exploring impacts on students and employability. PARTICIPANTS WILL LEARN: • current automotive composite trends • strategies for pre-preg waste reduction • geopolymers and performance surface plies • how digital manufacturing can be used to bridge the composite skills gap Exploring Current Composite Trends with Teesside University September 20, 2017 • 11:00 AM EST REGISTER TODAY FOR WEBINAR AT: http://short.compositesworld.com/Siemens920