The use of PP tubes at temperatures below zero centigrade must be carefully tested under real conditions as the load on the tubes can be very different depending on the medium to be frozen and the routine conditions. We are able to give you some tips on the basis of our experience and tests we have carried out on PP tubes.
In principle, with products made of PP, the strength values are reduced at temperatures below 0°C, and it is therefore necessary to ensure that the frozen tubes are not exposed to any particular mechanical loads (e.g. do not let the tubes fall off the table). The freezing conditions must be selected such that the content can be evenly frozen or frozen from the bottom to the top. Cracks caused by strain can occur in the lower part if the upper part of the tube freezes first as a result of unfavourable freezing conditions. For example, depending on the diameter of the hole, stands made out of Styrofoam have a strongly insulating effect which makes it more difficult to ensure the even freezing of the tubes. In principle, the tubes should have sufficient room to expand in a stand or storage container. Due to the large number of possible influence factors, we recommend you carry out a freezing test under your routine conditions.