Cryogenic labeling is one of the industry’s more esoteric applications. It is used by clinical and biomedical research laboratories, and in similar scientific environments, to identify plastic and glass vessels. These then undergo long-term cryogenic storage in liquid nitrogen or deep freezing. No prizes for guessing that polyester film is the only substrate that can withstand this and similar extremes of temperature.
For European converters these two factors combine with the introduction of two white polyester films by UK-based Madico Graphic Films, a subsidiary of the Japanese parent. The new labelstocks will withstand direct immersion into liquid nitrogen at -196ºC (-320.8ºF). They are said to offer a cohesive bond high enough to withstand thermal shock, eliminating the problem of delamination caused as a result.
Two 50-micron variants are available: one for desktop laser printing, and the other for thermal transfer printing using resin-based ribbons. Connection to a desktop PC allows the input of variable and fixed data from a laboratory’s database or other software application. As a substitute for traditional labeling methods and marking with a pen, Madico says combining desktop printing with the special polyester reduces the risk of human error caused by illegible marking or mislabeling. At the same time, users can print the extremely small batch and bar codes required on certain small vials and test-tubes, while ensuring the information remains clearly legible. The films were independently tested in accordance with the strict criteria of Southampton University’s specialist cryogenic department.