DIAB Divinycell sandwich composites aircargo container

The Next Generation of Air Cargo Container from Envirotainer

Envirotainer is the pioneer and leader in the development of active temperature-controlled air transportation solutions for pharmaceuticals and other temperature sensitive goods. It currently has a global rental fleet of over 3,500 active temperature control containers.

To maintain its leading position in this specialist area the company implemented a major project to develop the next generation of container that with an internal cargo volume of 6.38 m3 (224.2 ft3) would be a capable of handling larger shipments – five Euro or four US pallets. Key requirements of the new container were excellent thermal performance, high structural integrity and good impact resistance.

Following a four year development program, Envirotainer has launched its new RAP e2 container. This container represents a step change not only in terms of performance but also in the way that the container is manufactured.

Diab engineers have been working closely with the Envirotainer development team throughout the duration of the project providing materials and technical support. At the outset it was decided that sandwich composites based on Diab structural cores as opposed to the ‘traditional’ aluminum/polyurethane foam construction would offer improved thermal, structural and impact/damage performance.

With the decision to move to a sandwich composite design, the Envirotainer engineers developed a VARTM (vacuum assisted resin transfer molding) manufacturing process that would allow the efficient series production of the containers while at the same time maximizing the properties of the sandwich composites. In particular the process that Envirotainer has developed has allowed it to achieve high fiber fractions. Normally this is not the case with VARTM type processes.

With this process, matched rigid and flexible molds are used to create the two sandwich components that make up each container in a single shot. A particular feature of the Envirotainer VARTM system is that they have been able to achieve square internal corners to maximize cargo capacity. Usually for this type of process mold release angles would be necessary.

Full scale tests on the container have shown that it can withstand more than 23 ton static load on its roof.

In addition the new container offers almost twice the insulation value of an aluminum/ PUR equivalent container. This reduces the size of the battery pack for the temperature control system. In the case of the RAP e2 the interior temperature can be maintained at constant temperature (from -20 to +40 °C [-13 to +104 °F]) throughout the container’s journey (minimum of 35 hours).

Envirotainer also expects the RAP e2 to offer a higher resistance to damage than previous containers particularly in terms of size and propagation. However, in the event of accidental damage, the Envirotainer team has developed a repair scheme that only requires minimal composite/sandwich knowledge.


Louise Eriksson Jacka
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