1) Birthday balloon material 2) Film used for recording tapes 3) Floppy disk material 4) Helium balloon material 5) Helium-balloon material 6) Insulation material 7) Long-lasting balloon material 8) Plastic 9) Plastic brand 10) Polyester film brand 11) Polyester film trademark 12) Polyester sheet 13) Reflective material Found on https://www.crosswordclues.com/clue/mylar
The trade name of DuPont for their product used as thermal blanketing. It is a very thin material that has a shiny appearance. It is often used as an insulator in satellites, as well as for things on Earth like juice box packaging and emergency first-aid blankets. Found on http://www.daviddarling.info/encyclopedia/M/Mylar.html
metallic plastic available in sheet or plaited tube form. The tubing can be used to simulate scales on the flanks or fry imitating lures/streamer flies. Found on https://www.encyclo.co.uk/local/22502