Hey guys. So I’m experimenting with a way to keep a fairly large box/bin (about 22”x22”x22”) with heat sensitive material cool.(not frozen or even particularly cold, just not hot) my idea is to have said big box, filled with said heat sensitive product in smaller boxes inside it. And then have a small maybe 8x8” styrofoam bin of dry ice with an open top to just keep the air cool. This is for research for an idea a friend had and I’m just trying to think of ideas. I’m not attempting to transport or mail anything dumb like that, so the box won’t be being turned over and thrown around or handled in anyway. So I’m trying to figure out how to keep a box cool for a few days. It won’t be air sealed so I know the dry ice will just be eating away and off gassing, but I really just need to be able to take the edge off the temperature if it’s a really hot environment. Is this idea even worth looking into? Does dry ice work well or at all for giving off cold temps into an environment? I also have to make sure there’s no contact or unforeseen issues with having the off gassing and such. Certainly need to make sure I don’t flash freeze my product by accident. Also want to make sure cardboard and or packaging material won’t be damaged by the co2 In the air.
I’m researching some ideas for a problem a friend had and figured I’d tap into you fine people for ideas 
Fill a cooler with dry ice and put several towels over it before putting your smaller boxes
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You will need much more insulation from the dry ice to prevent things from getting well below freezing!
I made a “camping freezer years ago out of 2” 4X8 sheets of building foam insulation. It was 2 layers thick (4") everywhere but where I put the block dry ice it had an additional 2 inch layer, and it would freeze half gallon containers of water through the 2 inches of foam insulation every day and I would swap 8 of those out to keep 2 large ice chests cold. I also had 8 cases of sodas for the kids and watermelon as well as keeping ice cream for a 10 day trip on 100 pounds of dry ice and the sodas had 4" of insulation from the DI and were almost freezing at the end of the 10 days!
If I tell you the d/I secret of how to drop a bin down in temp you promise not to tell everyone.
get some 2” rtech foam or spray foam. Make sure you cover all 6 side. If you use 4” or rtech it’s the equivalent of a walk in.
https://www.homedepot.com/p/R-Tech-2-in-x-4-ft-x-8-ft-R-7-7-Rigid-Foam-Insulation-310891/202532856
You also should caulk the seams. And get a pressure seal for the cap.
edit:
I learned this from working with coolbot device.
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The fastest way to cool a 55 gallon feed drum is like so. Cheapest and most powerful effect.
Take a drum and wrap two layers of that bubble wrap insulation - maybe even diff but it doesn’t need to be too crazy bc this is a rapid effect. It’s not for holding btu throughout time frame for cooling efficiency.
Now take a huge 6x48" or larger triclamp column. Weld the bottom sealed. Now fill 2/3 with acetone. Now fill with dry icee pellets. I believe if I’m not mistaken for every foot or so you have 12-15kw @ -50c cooling effect.
When you add the alcohol it will burn off dry ice very rapidly at first. Once it’s around 0 ish the dry ice stops burning off so much.
You can take barrels down with this cold finger tech in minutes ----- the the head explosion tech is where you have a second cold finger with ln2 and you don’t need transfer tanks bc you can use the diffusion stone right in it.
Please don’t tell anyone this tech or else we’ll see every china manufacture rebranding reseller jack this as thier own.
Patent# 420-fuckyou
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Thx for the tek, but you clearly didnt read OP’s question 
The cost on sending the OP’s package that way might bankrupt him! Lol!
I’m not sending a package so Weight doesn’t make a difference.
And yea I’m not trying to cool down a barrel either. Like I said my goal is to be able to keep the contents of a 22x22x22” box cool for 2-3 days. Or atleast minimize the heat exposure as much as I can.
Best bet is either use ice chest or styrofoam cooler with 4-6 pound slab of dry ice wrapped tightly in an inch of newspaper. Put in bottom with several layers of bubble wrap or foam between it and what you want to keep cold. The better the dry Ice is sealed off from what you don’t want to freeze the better. Or as @densone suggested make your own foam box.
bioscience companies send packages of 2 coolers nested with the smaller one with samples larger with dry ice all the time.
checkout a product called techni ice. It’s cheap and reusable and might do the trick for you, pending you seal properly.