Although significant marketing efforts have been made in recent years to reduce polymer use, the number of plastic bottles being discarded is increasing worldwide. The global environmental-socio-economic problem posed by polyethylene terephthalate (PET) bottles can only be solved by expanding large-scale recycling opportunities, while reducing the use of pure raw materials. In this article on the large quantities product of PET was upcycled with chemical foaming. During the experiments 2 m% chain extender and 4 m% chemical blowing agent and different amount of brominated flame retardant was used. The invested materials were examined with standard mechanical tests, scanning electron microscopy and UL-94 standard flammability test. After the investigation it was found that the crystallized blue PET bottle re-granulate can be used forming a flame retardant closed cell foam structure.