Siemens Smart Infrastructure has launched a new Sirius 3RQ4 coupling relay series whose housings are molded from Akulon K225-KS B-MB, a halogen-free, flame-retardant polyamide 6 developed by Envalior in collaboration with Siemens. The material contains 70 percent bio-based content derived from biomass waste, specifically used cooking oil sourced from the food industry, restaurants, snack bars and households. Since used cooking oil is no longer suitable for human or animal consumption, it does not compete with food or feed production. Envalior applies a mass balance approach to convert this feedstock into engineering plastics, diverting the oil from incineration. The new relays meet the Siemens EcoTech label criteria, which include a 33 percent reduction in energy losses in the semiconductor variant compared to previous versions and the elimination of problematic substances such as halogens or PFAS. Andreas Matthé, CEO of Electrical Products at Siemens Smart Infrastructure, said: "Collaborating with Envalior to create this bio-based plastic is an important step towards advancing the use of more sustainable materials in our electrical products. We are pleased to work with Envalior as another strong partner on our journey towards a more environmentally friendly portfolio."
Material and sourcing
Akulon K225-KS B-MB is a PA6 grade for injection molding that combines a bio-based share from waste biomass with electrical performance suitable for power distribution and related applications. According to Envalior, the grade delivers high heat resistance, excellent chemical resistance and halogen-free flame retardancy, achieving a UL94 V-0 rating at 0.4 mm. Dr. Marc Rudolf, Global Key Account Manager at Envalior, commented: "At Envalior, we are proud to have partnered with Siemens in the development of the Sirius 3RQ4 coupling relay series. A key success factor in this project was achieving excellent flow behavior in thin-wall designs and a UL94 V-0 rating at just 0.4 mm thickness, while simultaneously achieving an outstanding green share from bio-waste sources but at prime quality."
Product variants and performance
The Sirius 3RQ4 coupling relays are available in three variants for different operating needs. The first variant with integral relay output targets harsh environments and applications with specific safety requirements. It features safety-ready characteristic values, including B10d values, and carries approval for potentially explosive atmospheres, ATEX-certified. Options include gold-plated contact elements for reliable switching of very low currents, as well as printed circuit boards with protective coating for railway applications.
The second variant is a plug-in coupling relay designed for quick relay replacement during operation. It is also available with optional gold-plated contacts. For applications that demand very fast, soundless and frequent switching, the third variant uses a semiconductor output. With a virtually infinite service life, it is suitable where replacing conventional relays is costly or time-consuming. Siemens increased the switching capacity of these semiconductor versions to up to 6 A, aligning their performance with conventional elementary relays.
The new Sirius 3RQ4 coupling relay comes in three versatile variants for a wide range of industrial requirements.
Lifecycle, manufacturing and documentation
The series is designed for sustainability across the lifecycle, from development to end of service. The product can be dismantled and recycled, and the housing material avoids halogens and PFAS. The relays feature a space-saving slim-line design for optimized use in control cabinets and have been designed and extensively tested for operation with Siemens controllers. Fully automated production at Siemens' Amberg plant shortens the supply chain for the German and European markets. Packaging uses more sustainable cardboard in standard multi-piece formats, and operating instructions and relevant information are provided electronically via an ID link on the device.
Process steps, from more sustainable raw material to finished coupling relays.
Energy and emissions targets at Envalior
Beyond bio-based materials, Envalior reports that in 2024 it covered over 50 percent of its global electricity demand with renewable sources. By 2030, the company aims to reduce emissions by a further 35 percent, supported by measures such as expanding renewable electricity to 100 percent by 2030, implementing local emission reduction initiatives and switching to climate-friendly heat sources. Envalior invests in renewable energy close to its production sites worldwide.
Trade fair presence
Envalior will present further information at K 2025, Hall 6, Stand B11, October 8-15, 2025, Messe Düsseldorf, Germany.
