Most of the polymers are susceptible to oxidative degradation either during processing – especially at the elevated temperature employed for higher outputs AND during the long-term service life of finished products.
It is used to remove moisture from the raw material. While melt processing, the combination of high shear, temperature, and oxygen can create oxidative degradation which results in discoloration, change in melt viscosity, and loss of physical and mechanical properties like surface crazing and embrittlement. During service lifetime the products are exposed to elevated temperatures outdoors and also atmospheric gaseous pollutants eg. Nitrogen oxides which lead to product losing strength as well as gas fading.
Though antioxidants are added to the resin by resin producers, these are consumable in nature and thus get depleted with repeated heat histories which the polymer undergoes eg. during recycling and reprocessing. Thus Antioxidant masterbatch help to replenish the reservoir of stabilizers to prevent product discoloration and failure during service. Thus whether the objective of adding recycled content is for sustainability or economics antioxidant masterbatches are critical for ensuring the product meets the expectations of end-users.
Antioxidant masterbatches are combinations of primary antioxidants which are usually phenolic and secondary antioxidants such as phosphites or thioesters and as a combination prevent thermos-oxidative degradation of polymers during both melt processing and service lifetime.
Some of the common applications are blown and cast films of LDPE, LLDPE such as mulch films, greenhouse films, reprocessed granules, rotationally molded items, HDPE pipes, etc. Anti Oxidant masterbatch can increase the OIT for HDPE pipes in critical applications.
- It is used to prevent process damaged.
- Make Product hydrophobic.
- Ease of processability