10/27/2011

www.gupta-verlag.de/thermoplastic-elastomers

New Santoprene grades help the automotive industry meet new challenges

1. New developments
These new developments include the Santoprene M200 Series, Santoprene 8211-85M350 TPV and robotic extrusion of Santoprene TPV. Santoprene M200 series
Santoprene 121-xxM200 grades are designed for glass encapsulated weatherseals for quarter lights and side fixed glass applications. They are also recommended for any other automotive injection molded parts, whether 1K or 2K, where aspect and optimal processing are critical. They exhibit a low dynamic viscosity which results in enhanced flow over a wide range of shear to produce molded seals with excellent surface appearance and no flow marks. [image_0]Processability is improved as the injection pressure can be reduced by about 30-40 percent, injection temperatures can be lowered by 10°C (50°F) and shorter cycle times are possible, depending on part size and wall thickness. This may lead to sustainability benefits through less glass breakage and lower energy consumption, along with the fact that TPVs are also fully recyclable. In addition, cost savings are possible due to simplified processing and reduced cycle times. Gloss levels of Santoprene 121-xxM200 TPV grades increase design flexibility, and specific mold graining can be used to match the surface aspect of extruded profiles. Santoprene 121-xxM200 TPV grades come with compression and tension set values comparable to those of EPDM rubber, and exterior UV-resistance that meets OEM specifications. Requiring lower injection pressure, the new TPV grades are less sensitive to flow direction during injection molding. As a result, there is less risk of part warping, making it easier to set process conditions and mold design. Santoprene 8211-85M350 for interiors
Thanks to its high-flow and specific concept, Santoprene 8211-85M350 is said to provide a unique "comfort touch” and excellent surface qualities for automotive interiors while offering significant cost reduction opportunities. The "comfort touch” prevents the cushion-like indentation that is often associated with alternative foamed material structures when pressed. As well as high "comfort touch”, it offers a range of benefits including low and stable gloss level, high scratch and mar resistance, good abrasion and chemical resistance, low fogging and odor emission. Also colorable, the material is well-suited for door panels, center consoles, B-C pillars, lower instrument panels and the back cover of seats. [image_1_right]"Santoprene 8211-85MM350 TPV is filling a gap for TPE-V use in the automotive industry, as its good optical and haptical properties can be applied to a broad range of automotive interior applications. The soft, low-gloss "comfort touch" achieved with Santoprene 8211-85MM350 TPV enhances the appearance of automotive interiors and provides a perception of high-quality to customers. Easy processability and the suitability for 2K injection molding offer an interesting cost saving potential, making Santoprene TPV a more cost conscious choice over other materials and established production concepts," said Mathias Dietz, manager sales and development, ETG Elastomer-Technik GmbH, based in Gedern, Germany. The material can be processed using 2K injection molding or mono-sandwich molding onto a rigid PP substrate to produce an unfoamed structure that does not indent. Either process provides an over-molded TPV skin with a high "comfort-touch”. It is an alternative to rigid PP, PP with soft-touch paint, and in some cases PVC or TPO skins.   Applications in the VW Multivan and Beetle
Fulfilling VW specifications - TL496 and VW50180 - for low fogging and odor, Santoprene 8211-85M350 is being used in the Multivan and Beetle. In the Multivan, it was chosen to produce a skin covering over a PP core for a top roll component of the door trim with an "integrated” arm rest function. The finished top roll component has a low gloss, "comfort touch” with a heat stable, highly durable surface. Easy to process, there are no flow lines and, with no secondary processing required, costs are reduced. In the Beetle, it is used as a skin over a PP core for the glove box to add a low gloss, "comfort touch”, heat stable component with high surface durability. It is also easy to produce, requiring no secondary processing and its low dynamic viscosity produces no flow lines.   Robotic extrusion
ExxonMobil Chemical and Reis Extrusion have jointly developed a robotic extrusion process for Santoprene that enables the cost-effective production of small to medium quantities of non-glass weatherseals. The process allows the extrusion of a flexible Santoprene TPV seal onto a substrate made from a range of materials, including plastic, metal, glass and nonwovens. Robotic extrusion is well suited for applications, such as cut line seals, cowl vent grill seals, weatherseals, hoses and tubes, and door module seals. The process delivers high levels of production flexibility, as seals can be extruded quickly and effectively. Part design changes can be accommodated by simply changing the die and process program, saving time and money. The technology enables production in one fully automatic step. The elimination of stages used in traditional systems - mixing, extrusion, curing, profile shipment, handling glue/clips and profile assembly onto the substrate - reduces assembly and logistics costs through integration and elimination of adhesives or mechanical attachment mechanisms. With no gluing or curing time required, parts can be handled immediately, saving time. "Reducing part cost and shortening the time to market, from the first sample to production, are some of the challenges facing the automotive industry. Robotic extrusion can play an important role in helping to meet these challenges because it is a fully automated, highly flexible production process. It allows the production of different profile geometries on the same extrusion line, but at a significantly lower investment cost compared to, for example, 2K injection molding. This high design flexibility for profile geometries, combined with the proven performance of Santoprene TPV and our processing experience, can be the foundation for more economical and faster application development," said Thomas Bischof, General Manager, Reis Extrusion GmbH, Merzenich, Germany. The first commercial components to be produced using this patent protected process were static weatherseals robotically extruded onto vehicle windows and seals on large polypropylene underbody panels.   Award-winning sealing solution for Faurecia
For Faurecia Interior Systems, ExxonMobil Chemical and Reis Extrusion focused on how robotic extrusion of Santoprene could reduce the weight and cost of a 360° seal for a door core module, while improving sealing performance. The first step in the process is injection molding a glass-filled ExxonMobil PP resin for the door core. The second step involves the robotic extrusion of a lighter-weight, hollow seal made of a specifically designed Santoprene grade. Because of its specific design, the 121-50E500 TPV grade allows seal profiles to maintain their shape without any further support, curing or calibration. It also provides essential sealing and bonding characteristics with no gluing or curing time required. As a result, parts can be handled and transported almost as soon as the robot has moved away saving tack/cure time by 90 %. At Faurecia, the robotic extrusion process is setup in such a way that the left- and right-hand door modules are injection molded, component sub-assemblies installed, and core module seals applied by one system. The one-piece module is assembled onto the door structure at the assembly line in a single step, eliminating several expensive assembly steps required in traditional systems. Compared to polyurethane or EPDM rubber, seals made of TPV provide reduced costs for both assembly and logistics. This is achieved through integration, sealing performance improvements due to its inherent properties (excellent compression stress relaxation, temperature resistance and adhesion to PP that ensure correct positioning of the seal) and lower weight. Such was the success of Faurecia's extruded seals on Chrysler's Dodge Nitro and Jeep Liberty, that they won an SPE Automotive Division Innovation Award. Santoprene TPVs are well suited for many flexible part applications because they can deliver enhanced performance through durable sealing capability combined with upgraded aesthetics of the finished part, reduced system costs due to simplified processing and design flexibility, that allows the manufacture of complex parts using 2K injection molding with other polymers, and potential sustainability opportunities through part weight reduction, re-use of in-process scrap and end-of-life part recycling within the polyolefin stream   2. General benefits of Santoprene Durable sealing
Over the life of a part, Santoprene TPVs offer a consistent sealing performance based on long-term aging durability combined with dimensional stability. They also exhibit very good physical properties including long-term compression set, low odor and fogging, as well as flexibility and good tear strength. Good aesthetics
The materials deliver upgraded aesthetics through better aspect harmonization between parts, "comfort touch” interior skins for a higher-end customer experience and enhanced surface appearance due to good flow characteristics and bonding properties with other materials. Lower-weight
Compared to thermoset rubber, they offer the opportunity to reduce part weight due to its lower density, part design optimization and material replacement opportunities. Ease of processing
The TPV materials can be easily processed on standard thermoplastics processing equipment resulting in more cost efficient processing and less waste during part manufacturing. Easier processing combined with a broad processing window enables reduced line start-up times and scrap reduction. Meanwhile, simplified processing through 2K injection molding and tighter tolerances on molded parts reduces trimming and rework compared with thermoset rubber. Design flexibility
Ease of processing combined with the suitability for coextrusion with other polymers enables product designers to tailor and simplify multipart system designs. Recyclability
As polyolefins, Santoprene TPVs are fully recyclable, either as in-process scrap, or at the end of part life. This reduces waste and cost, and helps to ensure regulatory compliance. In-process scrap can be reused after regrinding and end of part life recycling is possible within the polyolefin stream. Sustainable manufacturing
They also contribute to a more environmentally-friendly production process through lower energy consumption during manufacturing, elimination of chemicals and a smaller manufacturing site footprint. Because parts made with Santoprene TPV do not require heat curing during manufacturing, they may use up to 50 percent less energy than alternative material solutions. Fewer chemicals are used due to the eradication of spray coatings and adhesives and, typically, a TPV extrusion line takes only one-third the space of an EPDM line.

www.gupta-verlag.de/thermoplastic-elastomers