ASTM is a standards development organizations that provides technical standards for materials, products, systems, and services. The following testing methods are used for shrink wrap to test it’s strength and usability.
Coefficient of Friction
This test is used to determine the amount of friction between two surfaces of film. A sheet of film is wrapped around a metal sled, in such a way as not to produce wrinkles on the surface. This weighted sled is then pulled across the surface of another sheet of film. The amount of force required to initiate movement and sustain it is then recorded.
The results of this test are used to determine the slip properties of film.
Elongation is the amount of stretch, recorded as a percentage, a film sample will reach at a breaking point compared to the toughness sample length
This percentage is a barometer of the toughness of film.
Determines the amount of uninhibited shrink potential, shown as a percentage, a film sample has at a specific temperature. A swatch of film is immersed in a hot liquid for a specified time period, following which the shrink percentage is recorded in both directions.
This test is a gauge of a film’s ability to conform to a package.
Haze is the property of a film to scatter light and cause it to have a cloudy appearance. An incandescent light source is placed behind a film sample and geometrically located photocells behinds the film record the scattered light.
Film gauge has a bearing on test results and should be noted along with test data.
The brightness or sheen of a film. A light source is aimed at a specific angle at the film and a photosensitive receptor records the amount of light reflected.
Gloss is a good indicator of the cosmetic retail appeal of a film.