Thermal Shock Resistance Of Milk Bottles

The use of thermal shock tests is discussed and a suitable test for milk bottles is described. The percentage of bottles cracked (up to 50%) as a function of the thermal differential was determined on two lots of bottles. Repeated thermal shocking of bottles at a given temperature differential in laboratory tests, and repeated washings of bottles from the same lot in a commercial washer, both resulted in continual cracking with successive shocks. Washings during which the machine stopped, resulted in more thermal shock cracking than washings during which the machine ran continuously.