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13. March 2017

Composites for cost-effective lightweight construction

Covestro is presenting material solutions and technologies for the automotive, electronics and construction sectors as well as for the generation of renewable energies at the JEC World 2017 in hall 5A, stand L9. The developments set out below are based on the company’s product and process expertise for composites.

Covestro has developed the new Desmocomp PU matrix, which is ideally suited to outdoor applications, e.g. in side elements for Sortimo’s new System-Unit. (Source: Sortimo)

Covestro has developed the new Desmocomp PU matrix, which is ideally suited to outdoor applications, e.g. in side elements for Sortimo’s new System-Unit. (Source: Sortimo)

While searching for a matrix material with good UV, weather and chemical resistance, the company developed a new polyurethane system. Named Desmocomp, it is formulated from aliphatic isocyanates and is ideally suited to outdoor applications. Covestro is being declared a “Composite Champion” at the fair for this development, earning it one of the JEC Innovation Awards.

Lightweight vehicle components

Desmocomp can be processed cost-efficiently, thanks primarily to its long pot life and rapid curing, which also make the matrix material ideal for use in outdoor applications. One current application example are the weather-resistant, glass fibre-reinforced composites that development partner Sortimo International GmbH recently presented in the form of components for prototypes of its System Unit, a storage solution for light commercial vehicles.

Working with prominent partners from the automotive industry, Covestro has also developed another polyurethane matrix system that is part of the Baydur series. The advantage of this system is that the carbon fibre composites can absorb three times more energy than comparable resin systems. The material ensures high-level occupant safety in the event of a collision, says the company. The first prototypes received positive reviews during material testing. Thanks to the HP-RTM process with cycle times of just a few minutes, production of the components is very efficient.

Covestro has developed a new composite technology based on thermoplastic materials and carbon fibres. This enables an efficient manufacture, e.g., of thin-walled housings. (Source: Covestro)

Covestro has developed a new composite technology based on thermoplastic materials and carbon fibres. This enables an efficient manufacture, e.g., of thin-walled housings. (Source: Covestro)

Prepregs for cost-effective lightweight construction

Thanks to a new Baydur casting resin system, Covestro says it has become the first to successfully achieve industrial-scale production and processing of storage-stable polyurethane prepregs. They offer a cost-effective alternative to epoxy prepregs, as they produce components with comparable mechanical properties at significantly lower production costs, says the manufacturer.

In the first stage of a two-stage production process, glass fibres are impregnated with the reactive resin, conditioned thermally, transitioned to a stable state in which they are not fully reacted and wound onto rollers with separating foil. In the second stage, they are taken out of storage and used to produce the component itself. Other advantages over epoxy resins include more consistent component quality and more cost-effective, energy-efficient production. The technology is also to be made adapted for use in other applications in the future.

New material for consumer electronics

Covestro has developed a new composite technology for the efficient production of casing parts for mobile electronic devices. Based on polycarbonates and carbon fibres, the new technology meets current demands for particularly thin, lightweight and yet robust parts. The company uses this system to produce continuous fibre-reinforced unidirectional tapes and sheets for further processing by its customers.

The thermoplastic composites (CFRTP) come into their own when used in consumer electronics products. They provide the best strength-to-weight ratio of all standard composites on the market and are suitable for cost-effective and flexible mass production, says Covestro. Two of the reasons for this are short cycle times – with minimal manual work – and high yields.

RocTool, a specialist in high speed heat and cool moulding solutions, will give a live demonstration of its new Induction Dual Heating (IDH) technology by showing the production of a laptop cover with a selection of thermoplastic materials including CFRTP composites from Covestro. The demonstration can be seen at RocTool’s stand A32 in hall 6. The company presented their new IDH moulding process for the first time at K 2016, together with Flex, an electronic manufacturer, and other partners such as Covestro.

More speed in pultrusion

Pultrusion is a technology that is suitable for continuously manufacturing fibre-reinforced plastics. Thanks to its high productivity and good product characteristics, it supports a diverse range of applications, particularly in the construction industry. One current example is a window frame applications, where the high strength plus the heat and noise-absorbing effects of the polyurethane composites are particularly beneficial.

Covestro is currently working with plant manufacturer KraussMaffei on further developing the pultrusion process. The aim is to use cutting-edge plant engineering to boost productivity in the manufacture of straight and curved profiles. This also involves developing new injection boxes. KraussMaffei is exhibiting the initial results at stand B38 in Pavilion 6 at JEC World 2017, where it will be presenting applications from the construction and wind power sector.

 collaboration with Hübers and Chongqing Polycomp International Corp., Covestro succeeded in manufacturing the first megawatt-scale PU rotor blade in Asia. (Source: Covestro)

collaboration with Hübers and Chongqing Polycomp International Corp., Covestro succeeded in manufacturing the first megawatt-scale PU rotor blade in Asia. (Source: Covestro)

Cost-effective production of rotor blades

Power generation based on renewables is another key part of Covestro’s sustainability concept. The need for more cost-effective ways to produce wind turbines is greater than ever if we are to make more intensive use of wind energy, says the company.

Covestro has developed a special polyurethane infusion resin for the manufacture of rotor blades. In combination with reinforcing glass fibres from the company’s partner Saertex and an efficient production process from Hübers, the resin enables short cycle times. This gives manufacturers a clear cost advantage. After all, rotor blades account for around a quarter of the total cost of new wind turbines. The resin also exhibits very good mechanical properties, says Covestro.

Optimal effect of glass fibres

To fully exploit their ability to reinforce plastics, glass fibres are coated with sizing immediately after their manufacture. This protects the glass fibres from mechanical damage that could occur during subsequent processing. However, the real purpose of the sizing becomes evident in glass fibre-reinforced plastic composites, where it is partially responsible for the mechanical bond between the plastic matrix and the fibre surface, and therefore for the strength of the composites.

Waterborne polyurethane dispersions from the Baybond line of Covestro are used as film formers in glass and carbon fibre sizings for thermoplastic composite materials. The dispersions boast very good film formation, elasticity, adhesion and yellowing stability and can withstand high levels of mechanical stress. In addition, some Baybond products also satisfy European Regulation EU 10/2011 for plastics that come into contact with foods.

Besides continuously expanding its product portfolio for thermoplastic applications, Covestro is also currently working to extend the Baybond family by adding products for thermosetting applications.

www.covestro.com

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