Shrink film testing to determine shrink percentage and shrink force.
Intertek labs test client shrink film samples to e.g. determine the shrink-percentage and shrink-force properties.
Shrink percentage and shrink force testing:
- Shrink-percentage is determined by immersion of the film in an oil-bath at a chosen temperature. The shrink-percentage in machine- and transverse direction is monitored as a function of time.
- Shrink tension determination is based on DIN 53369. The test sample is attached to a load cell and is placed briefly in a hot oven and subsequently cooled down to room temperature. The force that is build up during the shrinking of the material is recorded.
Shrink-film is used as an over-wrap on many types of packaging. When heat is applied to the film it will shrink tightly over the object it is covering. The shrinkage of the films is based on the relaxation of the orientation stresses introduced in the film during the production of the film. The relaxation causes a good enclosure of the package.
