Japanese elastomers bounce to Texas

Styrenic elastomers from Japan will soon become more widely available in North America. Through its Septon America subsidiary, Kuraray Company Ltd. next month opens a production and technical service facility near Houston, TX. There, the company will produce a wide variety of styrenic block copolymers-not just commonplace SEBS but also higher-performing SEP, SEPS, and SEEPS. According to Ronald Foster, Septon's market development manager, the latter three grades are based on isoprene rubber and are fully hydrogenated. Together, these two attributes translate to improved thermal, mechanical, and UV-resistance properties compared to ordinary SEBS. "In many applications, these materials would be interchangeable," says Foster. "But there are subtle property differences." SEPS, for instance, exhibits the best flex properties over widely ranging temperatures, while SEEPS has the best overall mechanical properties. The prime use for all of these materials, which cover a wide range of hardnesses, will be in overmolding applications. "They have a non-oily feel that makes them attractive for consumer products," Foster notes. The new Septon plant also promises to increase the availability of the company's Hybrar materials. These proprietary styrenic block copolymers exhibit their peak sound and vibration damping properties at room temperature, Foster reports. Septon America Co.: Enter 515

It's all about the chemistry

A twist on Bayer Corp.'s thermoplastic polyurethane (TPU) chemistry has resulted in a new elastomer with enhanced weatherability and mechanical properties. This aliphatic TPU, called Desmopan ATPU, starts with a different feedstock than most TPUs-a straight-chain isocyanate rather than a cyclical. And this feedstock difference produces some advantages in the field, says Gerry DiBattista, a TPU specialist for Bayer. "ATPU doesn't yellow and its colors don't fade when it's exposed to intense sunlight and other weathering conditions," he says. The new elastomer also exhibits roughly 10% improvement in elongation and tear resistance as compared to a standard TPU of the same hardness. Finally, the material has shown good bonding characteristics to a variety of substrates, including ABS, polycarbonate, polystyrene, copolyesters, and others. "On ABS substrates, for example, we've seen bond strengths better than 50 pli," DiBattista reports. With its resistance to color shift and its bonding characteristics, ATPU targets overmolded components that see outdoor use. The new materials range in Shore hardness from 85A to 65D. Bayer Polymers: Enter 516

Elastomers made to order

The elastomer line-up from RTP Co. now includes "home made" styrenic block copolymers (SEBS and SBS) and a thermoplastic vulcanizate (TPV). According to Paul Killian, who manages the company's elastomer products, RTP in the past sourced the basic material for these three elastomers from other suppliers. The company would then modify the commercial elastomers, imparting properties such as electrical conductivity, flame retardancy, special effects coloring, wear resistance, and enhanced bondability. Now, the company can make and customize these specialty elastomers with a single pass through the compounding line, preserving mechanical properties and lowering costs, Killian reports. The new materials cover a hardness range from 30 Shore A to 75 Shore D. RTP Co.: Enter 517