a thermo - mechanically stable , heat sealable mono - axially oriented polymer substrate film includes polymers based on low density polyethylene . the thermo - mechanically stable , heat sealable mono - axially oriented polymer substrate film can consist essentially of the polymers based on low density polyethylene . the disclosure also describes a vapour deposition coated substrate film , especially such a film which is metallised , a packaging laminate comprising the vapour deposition coated polymer substrate film , and a packaging container produced from such a packaging laminate . also disclosed is a method for the production of the thermo - mechanically stable , heat sealable polymer substrate film and a method of vapour deposition coating the film .