How to conserve dry ice ?

What should be the best solution to conserve dry ice during a week ?

Thank you for your help.

Peter - Frankfurt/Main - Germany

Conservation :

In a Cooler (ice chest) : 18-24 Hours

Outside : 3-5 Hours

In Liquid : 15-45 Minutes

Dry ice lasts for a shorter period of time if it is not stored properly. It subliminates (turns from solid form to gas form) at a rate of about 2 to 5 Kg every 24 hours. So, if you need about 10 Kg of dry ice for the next day you need to buy 15 Kg the day before.

The best mode of preservation is an isothermal packaging made of polyurethane