Sub Zero Polypropylene Grade Selection for Packaging Molders
Heterophasic polypropylene copolymers with controlled rubber dispersion prevent brittle container shattering during sub-zero cold chain transport and drop impact.
Low Temperature Impact
Meaning
Evaluation of material toughness at temperatures below freezing determines the suitability of a polymer for cold environment applications. Measuring low temperature impact involves cooling the specimen to a target temperature, often minus twenty or minus forty degrees Celsius, before applying a dynamic load. This metric is essential for identifying the point where a plastic loses its ability to deform and becomes prone to shattering.
The testing ends once the material reaches its glass transition temperature or the lower limit of the cooling equipment.
Material Selection
Choice of resin for outdoor or refrigerated use depends heavily on the performance of the plastic in the cold. Since standard polymers become brittle as they lose thermal energy, a high low temperature impact value is a primary requirement for many consumer goods. Manufacturers often add elastomers or use specific copolymers to maintain flexibility.
These additives prevent the part from failing when dropped or struck in winter conditions.
Testing Protocol
Preparation for the test requires a long soaking period in a climate chamber to ensure the core of the plastic has reached the target temperature. Performing a low temperature impact test quickly after removal from the chamber is necessary to prevent the specimen from warming up. Variations in the soaking time can lead to inconsistent results.
Accurate sensors monitor the environment to maintain the integrity of the data.
Product Durability
Performance of a part in the field is directly linked to its resistance to cracking under cold stress. If a material has a poor low temperature impact rating, it will likely fail during shipping or use in northern climates. Broken components lead to warranty claims and damage to a brand reputation.
Strong materials ensure that safety equipment and automotive bumpers remain functional in all weather.