DuPont's new generation of high-efficiency, low-bulk products are designed to offer a perfect halfway house between single skins and heavy thermal quilts.
The ideal cargo cover for pharmaceutical applications is strong, light and compact. It must also be solar-reflective, weather-resistant and recyclable, and breathable, as well as particulate-impassable, X-ray penetrable, and easy to fit and remove. For low-temperature protection, the cover also needs to have adequate thermal insulation properties. Together, these requirements are a tall order.
Designed to bridge the gap between single-skin cargo covers and very bulky thermal quilts, from DuPont's latest covers have all these qualities and more. Products in its Tyvek Xtreme W50 class combine a highly UV-reflective outer surface with a low-emissivity inside coating and a high-efficiency fibrous thermal layer, while retaining full through-cover breathability. They perform as radiant shields as well as conduction barriers and can continuously evacuate water vapour to minimise condensation risks, as well as offering outstanding protection against rain, snow and wind.
While reusable cargo covers might seem to be an obvious idea, the long-distance return logistics associated with them can quickly wipe out any perceived cost and environmental benefits. Reusable covers need to be periodically inspected, cleaned, maintained, repaired and tested and aren't always available. By comparison, single-use covers offer guaranteed performance and, if made from eco-friendly materials, create no environmental deficit.
Instead of air-bubbles and thin, low-density foams, Tyvek's new cargo covers use a special PET fleece that is better able to maintain its thermal properties and can withstand more physical manhandling. Thin plastic membranes and air pockets, meanwhile, are prone to puncture, tearing and abrasion damage. Since perforated air bubbles offer practically zero insulation, too, such damage can lead to compromised performance.
Some types of insulating cargo cover are provided in roll form, which requires users to cut, fashion and fit the cover to a standard that will satisfy regulatory requirements. While a material may have passed the most stringent lab test, however, these results are of theoretical value if the efficacy of the protection is potentially compromised each time the product is used.
Bulk is another important issue. Covers based on voluminous bubble-wrap and multibubble-foil constructions are invariably difficult to store, unwieldy to handle and costly to transport. The new Tyvek Xtreme W50 covers, however, employ a high-efficiency, low-bulk PET fleece layer that is typically half the weight of its bubble-foil equivalent.
GDP regulations explicitly refer to humidity control as well as temperature. Excess moisture is a threat not only to product integrity, but also to packaging, usage/dosage directions and labelling. Since condensate formation is very environment specific, it is always advisable to minimise the risk by using breathable covers.
Handling damage during transport is never completely avoidable so when minor instances occur, it is important that they are visible and do not materially reduce protection. Unfortunately, damage to bubble-based materials is not always visible, but with PET fibrous insulation, small penetrations effectively 'self-heal' and minor abrasions have no detrimental effect on performance.