Flame Retardant Thermoplastic Composite
The continuous search for innovation in various markets (above all Automotive and Aerospace) finds unique opportunities in the field of thermoplastic composites.
Although there is a lot of experience and literature regarding thermosetting composites, the need to minimize waste and reduce pollution (as for the concept of circular or ‘green’ economy), is pushing the research towards those products that allow the possibility to be recycled at the end of their life. Such products must also allow higher productivity, with consequent use of lower quantities of energy and lower emissions of carbon dioxide and derivatives. We are talking, in fact, of thermoplastic composites.
The main processing technology for these materials is injection overmoulding, but extrusion is also becoming increasingly important. This allows the production of many meters of bilayer sheets (thermoplastic resin + fabric with reinforcement) which will then be thermoformed to fit different shapes and geometries for many application sectors.
The adhesion strength between the two components is the key factor since the interface between the materials is the most fragile part of the final piece. It is necessary to design the piece in the appropriate way and, most critically, to choose materials that have a chemical affinity between them.
In the Automotive market, we have been witnessing for several years the growing demand for electric cars, which guarantee the possibility of reaching a level of CO2 gas emissions close to 0 and which, at the same time, allow users to travel for long distances without having to stop many times to recharge. For this reason, there are more and more requests for materials that can adequately replace metal parts (giving weight reduction, with the further possibility of re-engineering the piece). But there is also a special demand in this sector for flame retardant properties - essential for all those materials that must be used for the construction of components where there is a passage of current (connectors, batteries, cooling systems for batteries, etc ...)
In this regard, Vamp Tech SpA, the Italian company specializing in flame-retarded thermoplastic compounds with over 30 years of experience, has developed a halogen free flame retardant UL94 V0 compound based on PP (VAMPLEN™ 0024 V0 C/Q), which can be easily processed in the extrusion process of Mitsubishi Chemicals to produce a sheet of flame-retardant thermoplastic composite (PP V0 + mat of random glass fiber).
The final product is a hybrid sheet (with a thickness of around 3 mm) suitable for thermoforming and flow-molding, which allows the creation of a wide variety of components and geometries, even of large dimensions. Those sheets exhibit low weight (density of the PP-based compound is 1.05 g / cm3), good mechanical resistance in all directions given by the random arrangement of the glass fibers in the mat, chemical resistance to different media, in addition to fire resistance.
The first interesting application of this product is a transportation box part dedicated to recreational off-highway vehicles. The composite is ergonomic and suitable for use at very low temperatures, thanks to its excellent impact resistance properties. The flame retardant characteristic of the container allows the possibility of transporting the most varied equipment (including electrical equipment) without the need for having special containers or packaging.
Furthermore, the use of a halogen-free flame retardant system guarantees low optical density and low toxicity of the fumes in the event of a fire, which makes the sheet attractive also for markets where these requirements are required, for example in all types of public transport (eg European Standard EN45545-2).