[FoodEng]

I need several (about 50-100 depending on size) plastic containers with a good seal that can withstand high temperatures of up to 50 C. I prefer rectangular or square-shaped that are standard lunch-box sized, so I can stack them on top of each other due to lack of storage space.  Currently, I'm imagining those plastic lunch or storage boxes. But I need them to have a tight lid/seal that can be opened, accessed, and reused when needed. I need a lot of them, so I prefer them to be cheap.

I will be storing salt solutions in these plastic boxes, so it has to be a plastic material where there won't be any reactions taking place. I will also be placing samples above those salt solutions, so I prefer that these boxes will come with some kind of rack or tray to hold these samples above the solutions.

Yeah, I know this is a lot. But if you can just suggest some good plastic boxes with a good seal, and then I can creatively design something or some method to hold the samples above the solutions.

[jaspevacek]

At least in terms of material selection, high density polyethylene would be a good choice. It does come in a food grade as well (assuming you moniker is meaningful).

[Honclbrif]

I think you can also get rectangular food containers made of polycarbonate which might do the trick. I've seen them around some commercial kitchens. A google search of " square polycarbonate food container" seems to turn up a few likely results.