2.1 The durability can be enhanced by using less different materials. The insulation, the housing and the lining could all be made from Expanded Polypropylene (EPP). This material in 100% recyclable. Less parts means less stock keeping units, countering dead stock and cutting costs.
2.2 Low tech solutions:
‘Terracotta has been used for water storage for centuries. Cooling occurs by natural evaporation through the pores of the terracotta material. Royal VKB’s Water Carafe is self cooling whilst standing in the sun on your garden table but is only suitable for serving water.’ http://www.royalvkb.com/productdet.asp?catid=1159
3.3 Degradation-resistant materials
Most foams that are used lose the Blow Agent gas resulting is less insulation.