Lloyd Instruments offers versatile testing of stretch wrap film with the introduction of two new test jigs for its LS1
1 kN (225 lbf) single column materials testing machine
. The TG1075 is used for testing puncture resistance to ASTM D 5748-95 (Re-approved 2007), while the TG1167 is used for testing peel cling to ASTM D 5458-95 (Re-approved 2001). In addition, the LS1 test machine
can be used to perform a standard tensile test
on stretch wrap film at very low force.
Stretch wrap film is an extremely important packaging material used in applications from heavy duty pallet strapping to sealing food items in containers to keep them fresh. Peel cling and puncture resistance are important parameters since cling is critical in maintaining a tight wrap after an item is stretch wrapped to prevent the film from unwrapping during handling and transportation, while puncture strength is important with regards to preventing accidental puncture damage thereby helping to maintain product freshness.
The TG1075 features a jig containing a 102 mm aperture to support the stretch wrap film and a probe. The jig is locked onto the base of the LS1 test machine
using the machine anchor pin. A removable upper plate allows the film to be mounted and clamped onto the jig. The probe is fitted to the bottom of the load cell. The Puncture resistance test method imparts a biaxial stress to determine the resistance of film to the penetration of a probe at a single constant test speed of 250 mm/min.
For peel cling measurements, the TG1167 Jig is fitted to the LS1
. A film strip is adhered to a flat film attached to an inclined surface on the peel jig. The force required to remove the film strip from the flat film is measured.
The versatile LS1 test machine
can also be used for tensile testing
of stretch wrap film by equipping it with an EX800Plus non-contacting extensometer
. The film samples have to be perfectly parallel or prepared dumbbells and are typically tested using TG33, TG74 or TG10 tensile grips. The EX800Plus extensometer
provides travel of 800 mm and can readily accommodate the very long elongation that occurs during tensile testing
of this material.