Rethinking Plastics.
Boosting sustainability with top material efficiency and recycling capability.
PARAT Technology specialises on both light and sturdy plastic components for special-purpose and utility vehicles, not least camper vans. In order to improve the insulating properties and sustainability of these parts, Polyurethane is being replaced by recyclable particle foams. Back-foaming thermoformed parts entirely without the use of steam on a custom FILL plant not only reduced the energy consumption and cycle time. It also facilitates manufacturing sandwich parts with greater stiffness and direct integration of sensitive functional or electronic components.
Plastics have changed the world; they have become an indispensable part of our daily lives. They for instance help reduce the weight of automobiles, thereby improving the vehicles’ fuel efficiency and carbon footprint. Furthermore, producing parts from plastics causes substantially less raw material and energy consumption than using metals. That is why automobile manufacturers use plastic parts for structural components as well as exterior parts and interior equipment.
Lightweight Components for Special-purpose Vehicles
Mainly for manufacturers of special-purpose vehicles, PARAT Technology GmbH + Co. KG develops and produces highly functional cladding parts and structural plastic components. A specialist for large parts with complex shapes with annual quantities ranging from 500 to 25,000, the Bavarian company supplies notable manufacturers of utility vehicles, construction and agricultural machinery, recreational vehicles such as dormobiles and of renewable energy generation equipment around the globe.
PARAT Technology is headquartered in Neureichenau, Germany, where Germany borders on Austria and the Czech Republic, and has additional locations in Hungary, Romania, and China. Following the recent takeover by senata GmbH, also located in Bavaria, the name is all PARAT Technology has in common with the well-known manufacturer of tool cases from which it sprang off in 1967.
“With our diverse, innovative range of technologies, we support our customers from the development phase through to the production of moulded parts for exterior and interior applications”, affirms Johannes Rosenberger, Head of Sales at PARAT Technology. “Our products combine the highest standards of design and performance, with a particular focus on sustainability.”
Rethinking Plastics
The parts manufactured by PARAT Technology are usually given their external shape by thermoforming, while their structural properties are achieved by back-foaming the deep-drawn parts, usually with polyurethane (PU). In order to meet high demands on the strength and rigidity of the parts with low weight, the company uses several processes, some of which were developed in-house, such as foam injection moulding (FIM) or long fibre injection (LFI) to produce glass fibre-reinforced components.
“These processes are mature and proven, but the use of PU foam has a serious inherent disadvantage”, says Johannes Rosenberger, Head of Sales at PARAT Technology. “Other than the thermoformed parts, PU foam is a thermoset, which cannot be recycled and is difficult to separate after processing.” In order to further reduce the carbon footprint of its products and increase their recycling rate, PARAT Technology looked for an alternative to PU foams.
One such alternative is particle foams such as EPS, EPE or EPP. This group also includes polystyrene, commonly known under the BASF brand name Styropor. Particle foams make highly complex shapes possible. At 20 to 300 kg/m3, they have an extremely low density and very high thermal and acoustic insulation values. This makes them ideal for the requirements of camping vehicle construction.
As they are supplied in the form of microgranules and are expanded immediately before moulding, particle foams also come with an extremely low transport volume. This further improves their eco-balance. Their main advantage, however, is the fact that they are thermoplastics. This implies that, along with the thermoformed parts, they can be part of a functioning circular economy.
New material calls for a new method
“Particle foams are nothing new; we have been producing fully automated systems for processing them since 1978”, says Wilhelm Rupertsberger, Head of the Plastics Competence Centre at FILL Gesellschaft m.b.H. This globally active Austrian mechanical engineering company has a long-standing partnership with PARAT Technology.
The conventional processes for so-called Particle Back Foaming (PBF) are based on the use of steam for both pre-foaming and foaming in the mould. This causes high energy consumption for its generation and long drying times for both the expanded foam beads and the finished parts. Using this process, their density cannot be controlled with precision. The fact that the vapour has to penetrate the parts also imposes severe restrictions in terms of geometry and surface finishing and prevents the integration of sensitive inserts.
In order to fully utilise the advantages of PBF, FILL has developed a new manufacturing process for particle foam processing. In this process, both the pre-expansion and the processing of the expanded foam beads in the mould are fully electric and vapour-free. This is why FILL refers to it as a dry PBF process.
Precisely controlled foam formation
Since mid-2024, the first productive PBF system using the new process has been in productive operation at PARAT Technology's main production site. Its first stage is a patented infrared pre-foaming system. There, the volume of the micro granulate is increased by a factor of 50 in several stages using infrared radiation, reducing the density of the material from about 650 g/l to 50 g/l.
"Thanks to the dry process, further processing of the expanded foam beads in the moulding tools can follow immediately without further drying or waiting time", says Heinz Hohensinner, Project Planning and Sales at FILL, citing a key advantage of infrared pre-expansion. "Energy consumption is around 10 percent lower than using the classic steam process." In addition, the density of the dry particle foam can be continuously and precisely controlled by microwave measurement.
The moulding revolution
The process patented by FILL for the production of particle foam mouldings overcomes the disadvantages of the previous state of the art. This is achieved by not feeding the heat required to create cohesive bonds between the foam beads directly into the granulate during the moulding process. Instead, the moulding tool is heated through integrated channels and transfers the heat to the plastic inside, a practice that has been tried and tested over several decades, particularly in plastic injection moulding. "Not only does this keep the material dry during heating, it also eliminates the inhomogeneities in the moulded body caused by the local steam supply openings," explains Heinz Hohensinner. "Using several heating circuits in a variothermal mould facilitates producing parts with zones of different strength in just one shot."
In the interests of high part throughput, the high-performance temperature control units in the FILL particle foam system do not only heat the moulds. They also cool the mould, so the moulded parts are solidified before removal, which can be performed manually.
New and more sustainable parts
As no vapour has to escape from the dry-moulded parts, the patented FILL process is not only suitable for the production of pure foam parts or the single-sided back-foaming of deep-drawn parts. In a process patented by PARAT Technology, two of these act as the outer and inner walls of a fully or partially closed sandwich structure. One example of this are so-called sleeping area extensions for camper vans. Installed instead of the rearmost side windows of the base vehicles, these body bulges allow a crosswise installation of the beds.
Moulded particle foam parts can also be functionalised by integrating inserts such as fastening, reinforcing or decorative elements. In view of the relatively low values of pressure and heat in the foaming process, it is even possible to integrate electronic assemblies, such as sensors or control elements, in a form-fit manner.
"The newly developed dry production process for particle foaming not only conserves resources and has an improved carbon footprint," explains Tobias Schmid, Head of Development at PARAT Technology, who acted as a development partner and pilot customer in the development of the new process by FILL. "It also enables us to produce completely new, significantly more sustainable cladding components with improved recyclability as part of a circular economy."
Maximum economic efficiency
PARAT Technology is using the FILL system for the steam-free production of particle foam moulded parts with a clamping dimension of up to 2 x 3 metres. In view of these dimensions, it has a very manageable footprint, not least due to the arrangement of the infrared pre-expansion system on a gallery. This was chosen so that the expanded material could be conveyed from there to the clamping unit with minimal energy.
As the FILL particle foam system is the first of its kind, those responsible at PARAT Technology wanted to play it safe. "At our request, FILL designed the clamping unit of the new system such that it is suitable for processing PU foam as well as particle foam", Johannes Rosenberger confirms. "As it gives us the opportunity to produce particle foam parts with previously unattainable properties at competitive costs, this will hardly ever become necessary."
About PARAT Technology:
PARAT Technology GmbH + Co KG, headquartered in Neureichenau (Germany) and with sites in Hungary, Romania and China, processes modern plastics into lightweight, sustainable and at the same time stable components for mobile machinery and leisure vehicles. The company is wholly owned by senata GmbH, based in Freising (Germany), and generated annual sales of around €120 million in 2023 with almost 1,100 employees.
PARAT Technology GmbH + Co. KG
Schoenenbach Strasse 1
94089 Neureichenau, Deutschland
+49 8583 29-0
www.parat-technology.com
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