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Direct integration of rubber foils in fiber reinforced plastics

News International-French

9 Feb 2016

The material consists of non cross-linked rubber foils, which can be directly integrated into existing manufacturing processes.

Fiber reinforced plastics (FRP) are in line with the market trend: their ratio of stability to weight makes them indispensable for use in motor sports, aeronautics and large series, such as mass transport and automotive applications. In addition to the costs, various other obstacles associated with the nature of the material itself also have to be overcome, such as acoustic properties, fragmentation and impact behavior.

To avoid these disadvantages, Gummiwerk Kraiburg developed Kraibon for industrial lightweight construction. The material consists of non cross-linked rubber foils, which can be directly integrated into existing manufacturing processes. Kraibon can be processed like prepreg, or pre-impregnated composite fibers; in the joint hardening process they produce a bond with fiber reinforced plastics (CFRP, GFRP, SMC, etc.) and with metals.

An essential characteristic of FRP is the high component stability in relation to the weight, which however results in low damping behavior and poor acoustic properties compared to conventional materials.

Kraibon improves the acoustic properties of FRP components: direct integration in the composition enables outstanding structure-borne sound attenuation of up to 20 dB with only very little additional weight. In addition, the weight reduction of about 2.5 kg/m² holds high innovation potential for manufacturers of indoor panels and floor tiles, for example.

Another important application for Kraibon is impact protection for components. Fiber reinforced plastics feature a polymer matrix that allows fixed and protected fibers to absorb the forces that occur. This works well in the direction of the fiber orientation, but in transverse direction the structure can break down relatively quickly. By integrating Kraibon into the material, components can withstand 100-300% higher impact energies. This allows either higher damage tolerances and therefore a longer life or cost-effective production of a lighter component that delivers the same performance.

Another disadvantage of FRP is its unfavorable fragmentation behavior – which is especially dubious in the case of passenger protection: in the event of a collision, normal CFRP components tend to break and shatter into many tiny pieces. The integration of Kraibon substantially improves the safety of the component. The elastomer layer is flexible and its excellent bonding holds the component together much better, thus minimizing fragmentation.

Kraibon also enables a level of quality in the hybrid combination of materials, such as metal and carbon. It functions in this case as a “glue” between the two materials. While conventional adhesives do not equalize the different expansion properties of metal and carbon when the component heats up, it compensates for these differences to create excellent adhesion on both sides. Another advantage is the electrical insulating property between the two materials, which prevents corrosion.

In conclusion, the new product is a flexible material with huge potential. It enables the exploration of new fields of application and therefore the improvement of products in order to gain a competitive edge.

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