Easy-flowing polyamides and polyesters deliver shorter cycle times, lower energy consumption

Lanxess (Köln, Germany) has expanded its range of easy-flowing polyamide (PA) 6/66 and polybutylene terephthalate (PBT) compounds, responding to what it says is market interest in the benefits that these materials offer in terms of processing, production costs and design freedom. “They are particularly suitable for manufacturing the kind of thin-walled components that are ideal for lightweight construction and the miniaturization of assemblies,” explains Tim Arping, a marketing expert at the Lanxess High Performance Materials (HPM) business unit.

The latest addition is Durethan BKV 30 XF (XtremeFlow). The PA 6 with 30 percent glass fiber content is the successor of Durethan DP BKV 30 XF and boasts more than  17 percent easier flowability (flow spiral, 8 x 2 millimeters, 280 °C melt temperature). Compared to Durethan BKV 30, another standard PA 6 with 30 percent glass fibers, its flowability is 62 percent higher.

The new material reportedly features a good mechanical property profile that is almost identical to that of its predecessor and also produces outstanding surfaces. “We think it has huge potential for use in applications such as light but extremely strong mounts and brackets in cars,” says Stefan Theiler, who is an expert in the development of polyamide compounds at HPM.

Also new are the three PA 6 compounds Durethan BG 30 X XF, BG 30 X H2.0 XF and BG 30 X H3.0 XF. They are reinforced with a 30 percent mix of glass fibers and glass microbeads and exhibit outstanding flowability and an exceptionally low susceptibility to warpage. Featuring a good mechanical property profile, their flowability is more than 30 percent higher than that of Durethan BG 30 X, a similar standard polyamide 6. “The compound with H3.0 thermostabilization has a very low copper and halide content and is customized for natural-colored and lightly colored applications in electrical engineering and electronics, such as plugs, plug connectors and fuse boxes. The H2.0 material version is aimed at components that are colored black and are subjected to higher heat loads,” says Theiler.

Lanxess also offers a wide range of easy-flowing Pocan XF polyester compounds. These materials include non-reinforced and reinforced products with flow properties that are usually much better than those of similar standard grades and are often more resistant to hydrolysis. “Furthermore, they exhibit an up to five percent reduced density, which means processors can save on material,” explains Boris Neuwald, product developer for Pocan at Lanxess.

One example of a non-reinforced PBT compound is Pocan B 1205 XF. Thanks to its outstanding flowability, this material is perfect for the trend toward miniaturization in the electrical engineering and electronics sectors. It is ideal for complex components with exceptionally thin wall thicknesses, such as mini plugs. When thin wall thicknesses of such components have to be combined with high mechanical stability, Pocan B 3217 XF is the material of choice. Neuwald adds: “This reinforced PBT with 16 percent glass fibers features a vastly improved fill behavior, particularly at low wall thicknesses. The glass fibers are therefore much more evenly distributed in narrow cavities than when using standard grades, which gives the component excellent mechanical stability.”

Further, the better a thermoplastic flows, the broader its processing window is. For example, processors can lower the melt temperature, which shortens cooling times and thus drives down cycle times, too. The end result is higher productivity. “For instance, Durethan BG 30 X XF helped to lower the melt temperature in the production of a fuse box by around 40°C compared to when using Durethan BG 30 X. That cuts the cycle time by 34 percent,” explains Theiler.

Alternatively, filling pressures can be lowered, thereby reducing mold wear and maintenance outlay and giving processors the opportunity to use smaller injection molding machines with lower locking forces, which saves costs and results in added flexibility. “In the case of a large fuse box, for instance, switching from Durethan BG 30 X to Durethan BG 30 X XF enabled the processor to lower the filling pressure for injection molding the part by some 500 bar. All four cavities of the mold could then be filled simultaneously, which doubled productivity,” says Theiler. “What’s more, easy-flowing thermoplastics can also be used to achieve higher injection speeds and better surface qualities,” he concludes.