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Please send all samples as URGENT DELIVERY to GunnLab as we will be CLOSED during the following days:
CLOSED 23th December onwards.
Reopening between 5th-9th January for URGENT CALLS AND SERVICES only
AND CLOSED between 10th-18th January. We'll reopen on 19th Jan and resume normal operations.
We appreciate your support, extend good wishes to our valued customers, and look forward to your business in 2026.
PHYSICAL PROPERTIES & MISCELLANEOUS TESTS
DYE-LEAK TEST
A dye liquid of high wetting ability is placed in the package. Any dye appearing on the outside of the package shows the existence and location of a leak. Any leaks found are photographed.
THERMAL SHRINKAGE - ASTM D2732
Locked in internal stresses may be released by heating. We measure the percentage of shrinkage that occurs in shrinkable packaging.
UV-VIS LIGHT TRANSMISSION
Graph of light absorbance vs wavelength.
THERMAL ANALYSIS
Differential Scanning Calorimetry (DSC)
Melting Point, Melting Range. Glass transition temperature (Tg) based on transition from a hard rigid state to flexible rubbery state. Heat of fusion (heat energy required to melt the polymer), Crystallinity.
Thermogravimetric Analysis (TGA)
Measures changes in weight as a sample is heated to high temperatures. Useful for measuring filler content of plastics, studying decomposition, etc.
OXIDATIVE INDUCTION TIME (isothermal OIT) - ASTM E1356, ISO-11357-6
Tests how well a plastic is protected from oxidation, and can show if the antioxidant in the plastic has been “used up” by excessive processing, weathering, etc.
WETTING TENSION "DYNES" ASTM D2578
Measure of liquid surface tension and the effectiveness of treatments applied to allow a surface to be printed (relates to adhesion of inks, coatings or adhesives).
COEFFICIENT OF FRICTION
(SLIP or COF) ASTM D1894
COF has a major influence on the way a film runs through packaging machinery.
Includes Static and Kinetic COF.
DENSITY - ASTM D792
Density can be used to identify a material, to follow physical changes, to assess uniformity, or to calculate strength-weight or cost-weight ratios.
MELT FLOW RATE (MFR) or
MELT INDEX (MFI) - ASTM D1238
Measures the viscosity, or rate of extrusion, of molten plastic.
This gives a relative indication of molecular chain length.
GELBO FLEX, HOT TACK, HAZE, ....
A large number of other tests complement those listed above.
