As this was some time ago you may already have solved this!
But nobody else has answered this so here goes:-
I bought a 2 liter insulated Canteen specially for the job. Mine was made in Spain, but you'll probably be able to find them wherever you live.
I am "Super Chilling" the Filtered Mineral Water first, in the Freezer, then when required mixing the CDS to the required strength and putting it in the Canteen with some CDS Ice cubes I'm now regularly making. This means that it starts nice and cool in there. The canteen also keeps out virtually ALL the UV from the hot sun here.
The manufacturer of my Canteen advertizes to keep the liquid cool for 8 hours.
On one occaision I found that the Ice Cubes were still "rattling around" inside, proving it to still be NICE n COOL still three and a half hours later! That's pretty good! Four hours later the Ice Cubes were gone, but it was still quite cool to taste.
The manufacturer doesn't go into detail, because there are at least two different types of plastic in the Canteen. However I think it may actually be three different types.
The outer case is marked as No 5 = PP. The Bottle Stop and Drinking Spout are both most probably the same, PP.
The insulation is definitely Expanded Polystyrene. This doesn't really matter, except to keep the drink cold.
The inner bottle that actually contains the liquid is of the "slightly-transparent-white-ish" type that could be either No2 = PE/HDPE or No5 = PP, but is unlikely to be No1 = PET (the "harder-transparent" kind). Unfortunately it's not marked which.
If possible get one with that inside bottle made from No2 - PE/HDPE. I'm planning on e-mailing the manufacturer to ask, before buying a replacement!
If the inside bottle is PP it won't last as long and the CDS will leach out some of the chemicals from the plastic, so beware. The "slightly-transparent-white-ish" plastic has a fair chance of being PE/HDPE?
Hope this helps - Greg
"Don't let the lying bxggxxs fool you anymore!"
Neither Politicians, Members of your "target" sex (whichever you happen to be), Businesspeople, Religious Frauds or Health Frauds!
Disclaimer:The protocols described on this site are official sacraments of the Genesis II Church of Health and Healing. The reader accepts 100% responsibility for any and all use made of any information herein.