PU spraying adds RIM to many applications

(China Coatings Online News) - Leichtform GmbH, a scientist in Bairnsdorf, Saxony, Germany, is developing a process for the production of lightweight, high-performance mixed mezzanine composites. He worked with scientists at the ILK Institute of Light Engineering and Polymer Technology at the University of Applied Science and Technology in Dresden, Germany, to develop the process. In addition, the project, directed by Professor Maik Gude of the same institute, focuses on mezzanine structures with very demanding production conditions and complex geometric shapes, and is funded by the Federal Ministry of Economy and Energy with the aim of completing the development of new processes in a short period of time, ensuring efficient manufacturing processes and preparing for mass production.Simple process handling increases productivityThe new processing process is inspired by the foaming polyurethane (PU) expansion reaction in the closed mold, after which the reactive PU mixture becomes a permeable semi-synthetic textile. In this way, the mold is filled close to the profile. The production of the foam core and the final impregnation of the mezzanine cover are carried out at the same stage. In addition, in addition to pure foam cores, this new process integrates unfiltered honeycomb paper structures.
High-performance mezzanine composites produced in the polyurethane spraying process with polymer cores and semi-form textiles (left, center) and integrated non-layered paper honeycomb (center) are compared to the structure of the muling layer with long cut-size fibers (right). (©TUD / ILK) 。 Until now, especially for structural materials with complex shapes, cores can only be manufactured in separate steps and then bonded to add layers to meet the structural requirements of the material. Now the new process has greatly improved this situation, there is no doubt that there is an advantage, because it can be in the same mold to create mezzanine structure fiber-reinforced mules and foam cores.according to the corresponding foam system, the production of the new process can be completed in about a few minutes. If the thermoplastic films are integrated together during the process, components with excellent surface quality are obtained, which is why varnishing of this part is not necessary in subsequent steps. In addition, inserts can also be embedded using foam for insert molding, allowing direct integration of sub-components without any complex machining steps.'s scientific work in the framework of the Shape project, which integrates textile-enhanced structures and thermoplastic filmsand led by engineer Oliver Weierenborn, is about processes that can be continuously produced based on polyurethane spraying and RIM reactive injection molding processes. The team of scientists is developing integrated textile reinforced structures and thermoplastic films, as well as load introduction elements suitable for a wide range of materials.plan to continue to study the performance range of mezzanine composites through comprehensive mechanical testing. Define the number of mules, foam density, and thickness of the layers according to the corresponding loads to obtain the custom structures necessary for complex geometry.
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