Determination of fusion temperature of polyethylene fiber sheets by Measuring Temperature of the Melting Surface (MTMS) method

MTMS stands for Measuring Temperature of the Melting Surface. It is a systematic approach to find the strongest peelable heat seal temperature for any two sealable materials. It involves analysis of the time-temperature profile, obtained by means of a thermocouple, to determine the temperature at which the strongest peelable heat seal can be obtained. This temperature is the fusion temperature, represented by an inflection point in the time-temperature profile. Previously, different flexible materials like HDPE, LDPE and OPP have been analyzed and successfully sealed using MTMS. TyvekRTM is DuPont's trade name for material made up of pure fibers of spun bonded high density polyethylene. Prior attempts to evaluate the inflection point for TyvekRTM were not successful, partly due to the effect of heat during the sealing process resulting in fiber destruction and ultimately decreased seal strength. This study found an inflection point for TyvekRTM and a strong peelable heat seal for easy opening of the TyvekRTM based packaging. In this study inflection point was evaluated using MTMS instrument. The strongest peelable heat seal was obtained near the inflection point, which is less than the melting point of the TyvekRTM being sealed. This technique was successfully implemented to obtain the temperature required to obtain a strong peelable heat seal for TyvekRTM 1073B.