All plastics have a minimum temperature rating. At this temperature the material becomes brittle and its impact strength has been significantly reduced causing it to be susceptible to cracking when under stress or pressure.
Water expands when frozen and the pressure this creates is sometimes enough to crack plastic, especially those that are brittle at temperatures below freezing. Room can be left in containers to account for this expansion but it is not always able to prevent damage to a container.
Polypropylene and PVC are both plastics that are brittle at temperatures below freezing. Polystyrene is considered brittle at 68°F and is very brittle at temperatures below freezing. High, medium and low polyethylene on the other hand, remains impact resistant at low temperatures. Polycarbonate and PETG also have low brittleness temperatures.
It is up to our manufactures to determine if a container is considered freezer safe or not. While it may be generally thought that plastic containers that are able to handle freezing temperatures without becoming brittle are safe, we can make no guarantees. We do recommend that when a plastic container is used that you leave enough head space to account for the expansion of the media being frozen.
The information contained in this article is for general information purposes only. The information is provided by
United States Plastic Corp. and while we endeavor to keep the information up to date and correct, we make no representations or
warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with
respect to the website or the information, products, services, or related graphics contained on the website for any purpose.
Any reliance you place on such information is therefore strictly at your own risk.
In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss
or damage, or any loss or damage whatsoever arising from loss of materials, time or profits arising out of,
or in connection with, the use of this information.