Abstract: Novel alloy/blends barrier resins consisting of a composition of Polyethylene Terephthalate (PET) and Polytrimethylene Naphthalate (PTN) or PET and Polybutylene Naphthalate (PBN) exclusively for packaging beverages like beer in a monolayer bottle outperforming the existing other barrier multi-layer bottles is described. The alloy/blends of PET/PTN and PET/PBN are produced by using in situ polymerization or melt blending the two polymers or compounding the two polymers to get the PTN and PBN in a PET polymer matrix. The composition of PET alloy/blends with PTN and PBN additionally contains other barrier improving additives. Incorporating a suitable oxygen scavenger in these new alloy/blends and converting to a stretch blow molded bottle, with or without heat setting, allows this monolayer bottle to be tunnel pasteurized for protecting beverages like beer filled at specific gas pressure to its maximum shelf life of >180 days keeping under control both oxygen ingress and carbon dioxide egress.