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Theller Engineering
707-762-3820
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CONDITIONING OF HEATSEALS
PRIOR TO TESTING |
The quick-test option offered in the Ultimate Strength mode is a very convenient and
time-saving feature, but it must be used with knowledge and judgment. There are a
number of polymers and blends that, when cooled to ambient temperature from a melt,
continue to change in heatseal strength for extended periods of time. It would not be
appropriate to test seal strength of these materials after only 30 seconds or less
cooling time. For them, option 3 - removal from machine for a conditioning period
prior to testing - should be chosen.
ASTM F88, "Standard Test Method for Seal Strength of Flexible Barrier Materials" calls
for conditioning heatseals for a period of 40 hours prior to testing, but permits a
shorter time if it has been shown to yield test results equivalent to those at the
standard period. Theller Engineering recommends the 10-30 second test be used only
when results have been shown to be equal to those at conditioning times previously
found to be acceptable.
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