What is the total amount of pressure required for the production of HDPE?

6-7 atm

High density polythene: It is formed when addition polymerisation of ethene takes place in a hydrocarbon solvent in the presence of a catalyst such as triethylaluminium and titanium tetrachloride (Ziegler-Natta catalyst) at a temperatureof 333 K to 343 K and under a pressure of 6-7 atmospheres.